From 89586a29f4fe26fc8e204b365060b5c22c858a03 Mon Sep 17 00:00:00 2001
From: Jason Larabie <jason@clockworklabs.io>
Date: Thu, 2 Apr 2026 12:34:09 -0700
Subject: [PATCH 1/8] Add the functionality to use NativeAOT-LLVM to build a P1
 .wasm (core module)

---
 .../BSATN.Runtime/BSATN.Runtime.csproj        |   5 +
 .../bindings-csharp/Runtime/Internal/FFI.cs   |  33 +++++
 crates/bindings-csharp/Runtime/Runtime.csproj |  10 +-
 crates/bindings-csharp/Runtime/bindings.c     |  19 ++-
 .../Runtime/build/SpacetimeDB.Runtime.targets |   2 +-
 crates/cli/src/subcommands/init.rs            |  52 ++++++--
 crates/cli/src/tasks/csharp.rs                | 120 +++++++++++-------
 .../Scripts/autogen/SpacetimeDBClient.g.cs    |   2 +-
 .../server-csharp/StdbModule.csproj           |  38 ++++++
 modules/sdk-test-cs/sdk-test-cs.csproj        |   5 +-
 .../regression-tests/client/client.csproj     |   5 +
 .../procedure-client/client.csproj            |   5 +
 .../republishing/client/client.csproj         |   5 +
 .../server-initial/StdbModule.csproj          |  38 ++++++
 .../server-republish/StdbModule.csproj        |  38 ++++++
 .../regression-tests/server/StdbModule.csproj |  38 ++++++
 16 files changed, 349 insertions(+), 66 deletions(-)

diff --git a/crates/bindings-csharp/BSATN.Runtime/BSATN.Runtime.csproj b/crates/bindings-csharp/BSATN.Runtime/BSATN.Runtime.csproj
index d58dad4cde4..4f6afaa8dd6 100644
--- a/crates/bindings-csharp/BSATN.Runtime/BSATN.Runtime.csproj
+++ b/crates/bindings-csharp/BSATN.Runtime/BSATN.Runtime.csproj
@@ -15,6 +15,11 @@
     <!-- <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles> -->
   </PropertyGroup>
 
+  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <TargetFrameworks>netstandard2.1;net10.0</TargetFrameworks>
+    <DefineConstants>$(DefineConstants);EXPERIMENTAL_WASM_AOT</DefineConstants>
+  </PropertyGroup>
+
   <ItemGroup>
     <!-- We want to build BSATN.Codegen both to include it in our NuGet package but also we want it to transform [SpacetimeDB.Type] usages in BSATN.Runtime code itself. -->
     <ProjectReference
diff --git a/crates/bindings-csharp/Runtime/Internal/FFI.cs b/crates/bindings-csharp/Runtime/Internal/FFI.cs
index 261233303dc..0fb30bb1a16 100644
--- a/crates/bindings-csharp/Runtime/Internal/FFI.cs
+++ b/crates/bindings-csharp/Runtime/Internal/FFI.cs
@@ -2,6 +2,12 @@ namespace SpacetimeDB.Internal;
 
 using System.Runtime.InteropServices;
 using System.Runtime.InteropServices.Marshalling;
+#if EXPERIMENTAL_WASM_AOT
+using WasmImportLinkageAttribute = System.Runtime.InteropServices.WasmImportLinkageAttribute;
+#else
+[AttributeUsage(AttributeTargets.Method, AllowMultiple = false)]
+file sealed class WasmImportLinkageAttribute : Attribute { }
+#endif
 
 // This type is outside of the hidden `FFI` class because for now we need to do some public
 // forwarding in the codegen for `__describe_module__` and `__call_reducer__` exports which both
@@ -190,6 +196,7 @@ public readonly record struct RowIter(uint Handle)
         public static readonly RowIter INVALID = new(0);
     }
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial CheckedStatus table_id_from_name(
         [In] byte[] name,
@@ -197,6 +204,7 @@ public static partial CheckedStatus table_id_from_name(
         out TableId out_
     );
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial CheckedStatus index_id_from_name(
         [In] byte[] name,
@@ -204,15 +212,18 @@ public static partial CheckedStatus index_id_from_name(
         out IndexId out_
     );
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial CheckedStatus datastore_table_row_count(TableId table_id, out ulong out_);
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial CheckedStatus datastore_table_scan_bsatn(
         TableId table_id,
         out RowIter out_
     );
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_4)]
     public static partial CheckedStatus datastore_index_scan_point_bsatn(
         IndexId index_id,
@@ -221,6 +232,7 @@ public static partial CheckedStatus datastore_index_scan_point_bsatn(
         out RowIter out_
     );
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_4)]
     public static partial CheckedStatus datastore_delete_by_index_scan_point_bsatn(
         IndexId index_id,
@@ -229,6 +241,7 @@ public static partial CheckedStatus datastore_delete_by_index_scan_point_bsatn(
         out uint out_
     );
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial CheckedStatus datastore_index_scan_range_bsatn(
         IndexId index_id,
@@ -242,6 +255,7 @@ public static partial CheckedStatus datastore_index_scan_range_bsatn(
         out RowIter out_
     );
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial Errno row_iter_bsatn_advance(
         RowIter iter_handle,
@@ -249,9 +263,11 @@ public static partial Errno row_iter_bsatn_advance(
         ref uint buffer_len
     );
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial CheckedStatus row_iter_bsatn_close(RowIter iter_handle);
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial CheckedStatus datastore_insert_bsatn(
         TableId table_id,
@@ -259,6 +275,7 @@ public static partial CheckedStatus datastore_insert_bsatn(
         ref uint row_len
     );
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial CheckedStatus datastore_update_bsatn(
         TableId table_id,
@@ -267,6 +284,7 @@ public static partial CheckedStatus datastore_update_bsatn(
         ref uint row_len
     );
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial CheckedStatus datastore_delete_by_index_scan_range_bsatn(
         IndexId index_id,
@@ -280,6 +298,7 @@ public static partial CheckedStatus datastore_delete_by_index_scan_range_bsatn(
         out uint out_
     );
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial CheckedStatus datastore_delete_all_by_eq_bsatn(
         TableId table_id,
@@ -288,9 +307,11 @@ public static partial CheckedStatus datastore_delete_all_by_eq_bsatn(
         out uint out_
     );
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_5)]
     public static partial CheckedStatus datastore_clear(TableId table_id, out ulong out_);
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial Errno bytes_source_read(
         BytesSource source,
@@ -298,6 +319,7 @@ public static partial Errno bytes_source_read(
         ref uint buffer_len
     );
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial CheckedStatus bytes_sink_write(
         BytesSink sink,
@@ -315,6 +337,7 @@ public enum LogLevel : byte
         Panic = 5,
     }
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial void console_log(
         LogLevel level,
@@ -352,12 +375,15 @@ internal static class ConsoleTimerIdMarshaller
         }
     }
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial ConsoleTimerId console_timer_start([In] byte[] name, uint name_len);
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial CheckedStatus console_timer_end(ConsoleTimerId stopwatch_id);
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_0)]
     public static partial void volatile_nonatomic_schedule_immediate(
         [In] byte[] name,
@@ -374,22 +400,28 @@ uint args_len
     // which prevents source-generated PInvokes from working with types from other assemblies, and
     // `Identity` lives in another assembly (`BSATN.Runtime`). Luckily, `DllImport` is enough here.
 #pragma warning disable SYSLIB1054 // Suppress "Use 'LibraryImportAttribute' instead of 'DllImportAttribute'" warning.
+    [WasmImportLinkage]
     [DllImport(StdbNamespace10_0)]
     public static extern void identity(out Identity dest);
 #pragma warning restore SYSLIB1054
 
+    [WasmImportLinkage]
     [DllImport(StdbNamespace10_1)]
     public static extern Errno bytes_source_remaining_length(BytesSource source, ref uint len);
 
+    [WasmImportLinkage]
     [DllImport(StdbNamespace10_2)]
     public static extern Errno get_jwt(ref ConnectionId connectionId, out BytesSource source);
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_3, EntryPoint = "procedure_start_mut_tx")]
     public static partial Errno procedure_start_mut_tx(out long micros);
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_3, EntryPoint = "procedure_commit_mut_tx")]
     public static partial Errno procedure_commit_mut_tx();
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_3, EntryPoint = "procedure_abort_mut_tx")]
     public static partial Errno procedure_abort_mut_tx();
 
@@ -400,6 +432,7 @@ public readonly struct BytesSourcePair
         public readonly BytesSource B;
     }
 
+    [WasmImportLinkage]
     [LibraryImport(StdbNamespace10_3, EntryPoint = "procedure_http_request")]
     public static partial Errno procedure_http_request(
         ReadOnlySpan<byte> request,
diff --git a/crates/bindings-csharp/Runtime/Runtime.csproj b/crates/bindings-csharp/Runtime/Runtime.csproj
index eb28d3481b6..af84834c7b2 100644
--- a/crates/bindings-csharp/Runtime/Runtime.csproj
+++ b/crates/bindings-csharp/Runtime/Runtime.csproj
@@ -15,6 +15,11 @@
     <RestoreAdditionalProjectSources Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-experimental/nuget/v3/index.json;$(RestoreAdditionalProjectSources)</RestoreAdditionalProjectSources>
   </PropertyGroup>
 
+  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <TargetFramework>net10.0</TargetFramework>
+    <DefineConstants>$(DefineConstants);EXPERIMENTAL_WASM_AOT</DefineConstants>
+  </PropertyGroup>
+
   <ItemGroup>
     <!-- Note: BSATN.Codegen is included in the BSATN.Runtime NuGet package. -->
     <ProjectReference Include="../BSATN.Runtime/BSATN.Runtime.csproj" />
@@ -28,9 +33,8 @@
 
   <!-- These must be explicit package dependencies so NuGet consumers can resolve the LLVM toolchain. -->
   <ItemGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
-    <PackageReference Include="Microsoft.DotNet.ILCompiler.LLVM" Version="8.0.0-*" IncludeAssets="All" />
-    <PackageReference Include="runtime.$(NETCoreSdkPortableRuntimeIdentifier).Microsoft.DotNet.ILCompiler.LLVM" Version="8.0.0-*" IncludeAssets="All" />
-    <PackageReference Include="Microsoft.NET.ILLink.Tasks" Version="8.0.0-*" Condition="'$(ILLinkTargetsPath)' == ''" IncludeAssets="All" />
+    <PackageReference Include="Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" IncludeAssets="All" />
+    <PackageReference Include="runtime.$(NETCoreSdkPortableRuntimeIdentifier).Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" IncludeAssets="All" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/crates/bindings-csharp/Runtime/bindings.c b/crates/bindings-csharp/Runtime/bindings.c
index f2d2d1ca919..6c4ed570949 100644
--- a/crates/bindings-csharp/Runtime/bindings.c
+++ b/crates/bindings-csharp/Runtime/bindings.c
@@ -265,9 +265,24 @@ WASI_SHIM(path_remove_directory, (int32_t, int32_t, int32_t));
 WASI_SHIM(path_rename, (int32_t, int32_t, int32_t, int32_t, int32_t, int32_t));
 WASI_SHIM(path_symlink, (int32_t, int32_t, int32_t, int32_t, int32_t));
 WASI_SHIM(path_unlink_file, (int32_t, int32_t, int32_t));
-WASI_SHIM(poll_oneoff, (int32_t, int32_t, int32_t, int32_t));
+int32_t WASI_NAME(poll_oneoff)(int32_t, int32_t, int32_t, int32_t nevents_ptr) {
+  if (nevents_ptr) {
+    *(__wasi_size_t*)(uintptr_t)nevents_ptr = 0;
+  }
+  // Returning success with uninitialized events can wedge the runtime.
+  // Fail explicitly so the caller surfaces the missing capability instead.
+  return __WASI_ERRNO_NOSYS;
+}
 WASI_SHIM(sched_yield, ());
-WASI_SHIM(random_get, (int32_t, int32_t));
+int32_t WASI_NAME(random_get)(int32_t buf, int32_t len) {
+  static uint32_t state = 0x13579BDFu;
+  uint8_t* out = (uint8_t*)(uintptr_t)buf;
+  for (int32_t i = 0; i < len; i++) {
+    state = state * 1664525u + 1013904223u;
+    out[i] = (uint8_t)(state >> 24);
+  }
+  return 0;
+}
 WASI_SHIM(sock_accept, (int32_t, int32_t, int32_t));
 WASI_SHIM(sock_recv, (int32_t, int32_t, int32_t, int32_t, int32_t, int32_t));
 WASI_SHIM(sock_send, (int32_t, int32_t, int32_t, int32_t, int32_t));
diff --git a/crates/bindings-csharp/Runtime/build/SpacetimeDB.Runtime.targets b/crates/bindings-csharp/Runtime/build/SpacetimeDB.Runtime.targets
index 5f183e0e040..ec8fac8b3b7 100644
--- a/crates/bindings-csharp/Runtime/build/SpacetimeDB.Runtime.targets
+++ b/crates/bindings-csharp/Runtime/build/SpacetimeDB.Runtime.targets
@@ -60,7 +60,7 @@
   <!-- TODO: remove when https://github.com/dotnet/runtime/issues/82788 is resolved. -->
   <Target Name="ObtainWasiSdk" BeforeTargets="_SetupWasiSdk;CheckWasmSdks">
     <PropertyGroup>
-      <WasiSdkVersion>24</WasiSdkVersion>
+      <WasiSdkVersion>29</WasiSdkVersion>
 
       <WasiSdkDownloadTempFile>$([System.IO.Path]::Combine($(IntermediateOutputPath), "wasi-sdk.$(WasiSdkVersion).tar.gz"))</WasiSdkDownloadTempFile>
 
diff --git a/crates/cli/src/subcommands/init.rs b/crates/cli/src/subcommands/init.rs
index bc95886a163..5aa8d1d2e71 100644
--- a/crates/cli/src/subcommands/init.rs
+++ b/crates/cli/src/subcommands/init.rs
@@ -1757,7 +1757,7 @@ pub fn init_csharp_project(project_path: &Path) -> anyhow::Result<()> {
     Ok(())
 }
 
-/// Adds NativeAOT-LLVM package references to an existing C# .csproj file and creates NuGet.Config.
+/// Adds NativeAOT-LLVM project configuration to an existing C# .csproj file and creates NuGet.Config.
 /// This is called when `--native-aot` is specified during `spacetime init`.
 fn add_native_aot_packages_to_csproj(project_path: &Path) -> anyhow::Result<()> {
     let csproj_path = project_path.join("StdbModule.csproj");
@@ -1767,26 +1767,60 @@ fn add_native_aot_packages_to_csproj(project_path: &Path) -> anyhow::Result<()>
 
     let content = std::fs::read_to_string(&csproj_path)?;
 
-    // The NativeAOT-LLVM ItemGroup to add
-    let native_aot_item_group = r#"
+    // The NativeAOT-LLVM configuration to add
+    let native_aot_config = r#"
+  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <TargetFramework>net10.0</TargetFramework>
+    <DefineConstants>$(DefineConstants);EXPERIMENTAL_WASM_AOT</DefineConstants>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <PublishTrimmed>true</PublishTrimmed>
+    <SelfContained>true</SelfContained>
+    <WasmEnableThreads>false</WasmEnableThreads>
+  </PropertyGroup>
+
+  <Target Name="UseWasiRuntimeOverlayWithoutComponentWit"
+          Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'"
+          AfterTargets="SetupProperties"
+          BeforeTargets="LinkNativeLlvm">
+    <PropertyGroup>
+      <_OriginalIlcSdkPath>$(IlcSdkPath)</_OriginalIlcSdkPath>
+      <_WasiRuntimeOverlayDir>$(IntermediateOutputPath)native-hidden-no-wit\</_WasiRuntimeOverlayDir>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <_WasiRuntimeOverlaySource Include="$(IlcFrameworkNativePath)**\*" Exclude="$(IlcFrameworkNativePath)**\*.wit" />
+    </ItemGroup>
+
+    <RemoveDir Directories="$(_WasiRuntimeOverlayDir)" />
+    <MakeDir Directories="$(_WasiRuntimeOverlayDir)" />
+    <Copy SourceFiles="@(_WasiRuntimeOverlaySource)"
+          DestinationFiles="@(_WasiRuntimeOverlaySource->'$(_WasiRuntimeOverlayDir)%(RecursiveDir)%(Filename)%(Extension)')" />
+
+    <PropertyGroup>
+      <IlcFrameworkNativePath>$(_WasiRuntimeOverlayDir)</IlcFrameworkNativePath>
+      <IlcSdkPath>$(_OriginalIlcSdkPath)</IlcSdkPath>
+    </PropertyGroup>
+  </Target>
+
   <ItemGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
-    <PackageReference Include="Microsoft.NET.ILLink.Tasks" Version="8.0.0-*" Condition="'$(ILLinkTargetsPath)' == ''" />
-    <PackageReference Include="Microsoft.DotNet.ILCompiler.LLVM" Version="8.0.0-*" />
-    <PackageReference Include="runtime.$(NETCoreSdkPortableRuntimeIdentifier).Microsoft.DotNet.ILCompiler.LLVM" Version="8.0.0-*" />
+    <PackageReference Include="Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" />
+    <PackageReference Include="runtime.$(NETCoreSdkPortableRuntimeIdentifier).Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" />
   </ItemGroup>
 "#;
 
-    // Insert the ItemGroup before the closing </Project> tag
+    // Insert the NativeAOT config before the closing </Project> tag
     let new_content = if let Some(pos) = content.rfind("</Project>") {
         let (before, after) = content.split_at(pos);
-        format!("{}{}{}", before.trim_end(), native_aot_item_group, after)
+        format!("{}{}{}", before.trim_end(), native_aot_config, after)
     } else {
         anyhow::bail!("Invalid .csproj file: missing </Project> tag");
     };
 
     std::fs::write(&csproj_path, new_content)?;
     println!(
-        "{} Added NativeAOT-LLVM package references to {}",
+        "{} Added NativeAOT-LLVM project configuration to {}",
         "✓".green(),
         csproj_path.display()
     );
diff --git a/crates/cli/src/tasks/csharp.rs b/crates/cli/src/tasks/csharp.rs
index 5df8b730448..cfac60422ea 100644
--- a/crates/cli/src/tasks/csharp.rs
+++ b/crates/cli/src/tasks/csharp.rs
@@ -17,46 +17,58 @@ pub(crate) fn build_csharp(project_path: &Path, build_debug: bool) -> anyhow::Re
         };
     }
 
-    // Check if the `wasi-experimental` workload is installed. Unfortunately, we
-    // have to do this by inspecting the human-readable output. There is a
-    // hidden `--machine-readable` flag but it also mixes in human-readable
-    // output as well as unnecessarily updates various unrelated manifests.
-    match dotnet!("workload", "list").read() {
-        Ok(workloads) if workloads.contains("wasi-experimental") => {}
-        Ok(_) => {
-            // If wasi-experimental is not found, first check if we're running
-            // on .NET SDK 8.0. We can't even install that workload on older
-            // versions, and we don't support .NET 9.0 yet, so this helps to
-            // provide a nicer message than "Workload ID wasi-experimental is not recognized.".
-            let version = dotnet!("--version").read().unwrap_or_default();
-            if parse_major_version(&version) != Some(8) {
-                anyhow::bail!(concat!(
-                    ".NET SDK 8.0 is required, but found {version}.\n",
-                    "If you have multiple versions of .NET SDK installed, configure your project using https://learn.microsoft.com/en-us/dotnet/core/tools/global-json."
-                ));
-            }
+    let experimental_wasm_aot = std::env::var_os("EXPERIMENTAL_WASM_AOT").is_some_and(|v| v == "1");
 
-            // Finally, try to install the workload ourselves. On some systems
-            // this might require elevated privileges, so print a nice error
-            // message if it fails.
-            dotnet!(
-                "workload",
-                "install",
-                "wasi-experimental",
-                "--skip-manifest-update"
-            )
-            .stderr_capture()
-            .run()
-            .context(concat!(
-                "Couldn't install the required wasi-experimental workload.\n",
-                "You might need to install it manually by running `dotnet workload install wasi-experimental` with privileged rights."
-            ))?;
-        }
-        Err(error) if error.kind() == std::io::ErrorKind::NotFound => {
-            anyhow::bail!("dotnet not found in PATH. Please install .NET SDK 8.0.")
+    if experimental_wasm_aot {
+        let version = dotnet!("--version").read().unwrap_or_default();
+        if parse_major_version(&version) != Some(10) {
+            anyhow::bail!(concat!(
+                ".NET SDK 10.0 is required for NativeAOT-LLVM C# builds, but found {version}.\n",
+                "If you have multiple versions of .NET SDK installed, configure your project using https://learn.microsoft.com/en-us/dotnet/core/tools/global-json."
+            ));
         }
-        Err(error) => anyhow::bail!("{error}"),
-    };
+    } else {
+        // Check if the `wasi-experimental` workload is installed. Unfortunately, we
+        // have to do this by inspecting the human-readable output. There is a
+        // hidden `--machine-readable` flag but it also mixes in human-readable
+        // output as well as unnecessarily updates various unrelated manifests.
+        match dotnet!("workload", "list").read() {
+            Ok(workloads) if workloads.contains("wasi-experimental") => {}
+            Ok(_) => {
+                // If wasi-experimental is not found, first check if we're running
+                // on .NET SDK 8.0. We can't even install that workload on older
+                // versions, and we don't support .NET 9.0 yet, so this helps to
+                // provide a nicer message than "Workload ID wasi-experimental is not recognized.".
+                let version = dotnet!("--version").read().unwrap_or_default();
+                if parse_major_version(&version) != Some(8) {
+                    anyhow::bail!(concat!(
+                        ".NET SDK 8.0 is required, but found {version}.\n",
+                        "If you have multiple versions of .NET SDK installed, configure your project using https://learn.microsoft.com/en-us/dotnet/core/tools/global-json."
+                    ));
+                }
+
+                // Finally, try to install the workload ourselves. On some systems
+                // this might require elevated privileges, so print a nice error
+                // message if it fails.
+                dotnet!(
+                    "workload",
+                    "install",
+                    "wasi-experimental",
+                    "--skip-manifest-update"
+                )
+                .stderr_capture()
+                .run()
+                .context(concat!(
+                    "Couldn't install the required wasi-experimental workload.\n",
+                    "You might need to install it manually by running `dotnet workload install wasi-experimental` with privileged rights."
+                ))?;
+            }
+            Err(error) if error.kind() == std::io::ErrorKind::NotFound => {
+                anyhow::bail!("dotnet not found in PATH. Please install .NET SDK 8.0.")
+            }
+            Err(error) => anyhow::bail!("{error}"),
+        };
+    }
 
     let config_name = if build_debug { "Debug" } else { "Release" };
 
@@ -68,15 +80,25 @@ pub(crate) fn build_csharp(project_path: &Path, build_debug: bool) -> anyhow::Re
         )
     })?;
 
-    // run dotnet publish using cmd macro
-    dotnet!("publish", "-c", config_name, "-v", "quiet").run()?;
+    if experimental_wasm_aot {
+        dotnet!(
+            "publish",
+            "-c",
+            config_name,
+            "-v",
+            "quiet",
+            "/p:IlcLlvmTarget=wasm32-unknown-wasip1",
+            "/p:WasmEnableThreads=false"
+        )
+        .run()?;
+    } else {
+        // run dotnet publish using cmd macro
+        dotnet!("publish", "-c", config_name, "-v", "quiet").run()?;
+    }
 
     // check if file exists
-    let subdir = if std::env::var_os("EXPERIMENTAL_WASM_AOT").is_some_and(|v| v == "1") {
-        "publish"
-    } else {
-        "AppBundle"
-    };
+    let subdir = if experimental_wasm_aot { "publish" } else { "AppBundle" };
+    let target_framework = if experimental_wasm_aot { "net10.0" } else { "net8.0" };
     // TODO: This code looks for build outputs in both `bin` and `bin~` as output directories. @bfops feels like we shouldn't have to look for `bin~`, since the `~` suffix is just intended to cause Unity to ignore directories, and that shouldn't be relevant here. We do think we've seen `bin~` appear though, and it's not harmful to do the extra checks, so we're merging for now due to imminent code freeze. At some point, it would be good to figure out if we do actually see `bin~` in module directories, and where that's coming from (which could suggest a bug).
     // check for the old .NET 7 path for projects that haven't migrated yet
     let bad_output_paths = [
@@ -91,8 +113,12 @@ pub(crate) fn build_csharp(project_path: &Path, build_debug: bool) -> anyhow::Re
         ));
     }
     let possible_output_paths = [
-        project_path.join(format!("bin/{config_name}/net8.0/wasi-wasm/{subdir}/StdbModule.wasm")),
-        project_path.join(format!("bin~/{config_name}/net8.0/wasi-wasm/{subdir}/StdbModule.wasm")),
+        project_path.join(format!(
+            "bin/{config_name}/{target_framework}/wasi-wasm/{subdir}/StdbModule.wasm"
+        )),
+        project_path.join(format!(
+            "bin~/{config_name}/{target_framework}/wasi-wasm/{subdir}/StdbModule.wasm"
+        )),
     ];
     if possible_output_paths.iter().all(|p| p.exists()) {
         anyhow::bail!(concat!(
diff --git a/demo/Blackholio/client-unity/Assets/Scripts/autogen/SpacetimeDBClient.g.cs b/demo/Blackholio/client-unity/Assets/Scripts/autogen/SpacetimeDBClient.g.cs
index 423b77b5cf4..e7febb6fa13 100644
--- a/demo/Blackholio/client-unity/Assets/Scripts/autogen/SpacetimeDBClient.g.cs
+++ b/demo/Blackholio/client-unity/Assets/Scripts/autogen/SpacetimeDBClient.g.cs
@@ -1,7 +1,7 @@
 // THIS FILE IS AUTOMATICALLY GENERATED BY SPACETIMEDB. EDITS TO THIS FILE
 // WILL NOT BE SAVED. MODIFY TABLES IN YOUR MODULE SOURCE CODE INSTEAD.
 
-// This was generated using spacetimedb cli version 2.0.0 (commit 6a6b5a6616f0578aa641bc0689691f953b13feb8).
+// This was generated using spacetimedb cli version 2.1.0 (commit 6cae7a4ca81a3c90d01d3f3303d46fa7bf7b3d41).
 
 #nullable enable
 
diff --git a/demo/Blackholio/server-csharp/StdbModule.csproj b/demo/Blackholio/server-csharp/StdbModule.csproj
index b19fb92460c..57a38def25e 100644
--- a/demo/Blackholio/server-csharp/StdbModule.csproj
+++ b/demo/Blackholio/server-csharp/StdbModule.csproj
@@ -12,8 +12,46 @@
     <NoWarn>$(NoWarn);CS8981;IDE1006</NoWarn>
   </PropertyGroup>
 
+  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <TargetFramework>net10.0</TargetFramework>
+    <DefineConstants>$(DefineConstants);EXPERIMENTAL_WASM_AOT</DefineConstants>
+  </PropertyGroup>
+
   <ItemGroup>
     <PackageReference Include="SpacetimeDB.Runtime" Version="2.1.*" />
   </ItemGroup>
+  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <PublishTrimmed>true</PublishTrimmed>
+    <SelfContained>true</SelfContained>
+    <WasmEnableThreads>false</WasmEnableThreads>
+  </PropertyGroup>
+
+  <Target Name="UseWasiRuntimeOverlayWithoutComponentWit"
+          Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'"
+          AfterTargets="SetupProperties"
+          BeforeTargets="LinkNativeLlvm">
+    <PropertyGroup>
+      <_OriginalIlcSdkPath>$(IlcSdkPath)</_OriginalIlcSdkPath>
+      <_WasiRuntimeOverlayDir>$(IntermediateOutputPath)native-hidden-no-wit\</_WasiRuntimeOverlayDir>
+    </PropertyGroup>
 
+    <ItemGroup>
+      <_WasiRuntimeOverlaySource Include="$(IlcFrameworkNativePath)**\*" Exclude="$(IlcFrameworkNativePath)**\*.wit" />
+    </ItemGroup>
+
+    <RemoveDir Directories="$(_WasiRuntimeOverlayDir)" />
+    <MakeDir Directories="$(_WasiRuntimeOverlayDir)" />
+    <Copy SourceFiles="@(_WasiRuntimeOverlaySource)"
+          DestinationFiles="@(_WasiRuntimeOverlaySource->'$(_WasiRuntimeOverlayDir)%(RecursiveDir)%(Filename)%(Extension)')" />
+
+    <PropertyGroup>
+      <IlcFrameworkNativePath>$(_WasiRuntimeOverlayDir)</IlcFrameworkNativePath>
+      <IlcSdkPath>$(_OriginalIlcSdkPath)</IlcSdkPath>
+    </PropertyGroup>
+  </Target>
+  
+  <ItemGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <PackageReference Include="Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" />
+    <PackageReference Include="runtime.$(NETCoreSdkPortableRuntimeIdentifier).Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" />
+  </ItemGroup>
 </Project>
diff --git a/modules/sdk-test-cs/sdk-test-cs.csproj b/modules/sdk-test-cs/sdk-test-cs.csproj
index 09cf1192bb7..19453d0b44f 100644
--- a/modules/sdk-test-cs/sdk-test-cs.csproj
+++ b/modules/sdk-test-cs/sdk-test-cs.csproj
@@ -10,8 +10,7 @@
     <ProjectReference Include="../../crates/bindings-csharp/Runtime/Runtime.csproj" />
   </ItemGroup>
   <ItemGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
-      <PackageReference Include="Microsoft.NET.ILLink.Tasks" Version="8.0.0-*" Condition="'$(ILLinkTargetsPath)' == ''" />
-      <PackageReference Include="Microsoft.DotNet.ILCompiler.LLVM" Version="8.0.0-*" GeneratePathProperty="true" />
-      <PackageReference Include="runtime.$(NETCoreSdkPortableRuntimeIdentifier).Microsoft.DotNet.ILCompiler.LLVM" Version="8.0.0-*" />
+      <PackageReference Include="Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" GeneratePathProperty="true" />
+      <PackageReference Include="runtime.$(NETCoreSdkPortableRuntimeIdentifier).Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" />
   </ItemGroup>
 </Project>
diff --git a/sdks/csharp/examples~/regression-tests/client/client.csproj b/sdks/csharp/examples~/regression-tests/client/client.csproj
index 540e15ad427..d63b7158f32 100644
--- a/sdks/csharp/examples~/regression-tests/client/client.csproj
+++ b/sdks/csharp/examples~/regression-tests/client/client.csproj
@@ -8,6 +8,11 @@
     <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
   </PropertyGroup>
 
+  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <TargetFramework>net10.0</TargetFramework>
+    <DefineConstants>$(DefineConstants);EXPERIMENTAL_WASM_AOT</DefineConstants>
+  </PropertyGroup>
+
   <ItemGroup>
     <ProjectReference Include="../../../SpacetimeDB.ClientSDK.csproj" />
   </ItemGroup>
diff --git a/sdks/csharp/examples~/regression-tests/procedure-client/client.csproj b/sdks/csharp/examples~/regression-tests/procedure-client/client.csproj
index 04759b33920..809f2112a87 100644
--- a/sdks/csharp/examples~/regression-tests/procedure-client/client.csproj
+++ b/sdks/csharp/examples~/regression-tests/procedure-client/client.csproj
@@ -10,6 +10,11 @@
     <NoWarn>$(NoWarn);CS0067</NoWarn> 
   </PropertyGroup>
 
+  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <TargetFramework>net10.0</TargetFramework>
+    <DefineConstants>$(DefineConstants);EXPERIMENTAL_WASM_AOT</DefineConstants>
+  </PropertyGroup>
+
   <ItemGroup>
     <ProjectReference Include="../../../SpacetimeDB.ClientSDK.csproj" />
   </ItemGroup>
diff --git a/sdks/csharp/examples~/regression-tests/republishing/client/client.csproj b/sdks/csharp/examples~/regression-tests/republishing/client/client.csproj
index 9c07c1d1c1b..1bbdfd8c02f 100644
--- a/sdks/csharp/examples~/regression-tests/republishing/client/client.csproj
+++ b/sdks/csharp/examples~/regression-tests/republishing/client/client.csproj
@@ -7,6 +7,11 @@
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
+  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <TargetFramework>net10.0</TargetFramework>
+    <DefineConstants>$(DefineConstants);EXPERIMENTAL_WASM_AOT</DefineConstants>
+  </PropertyGroup>
+
   <ItemGroup>
     <ProjectReference Include="../../../../SpacetimeDB.ClientSDK.csproj" />
   </ItemGroup>
diff --git a/sdks/csharp/examples~/regression-tests/republishing/server-initial/StdbModule.csproj b/sdks/csharp/examples~/regression-tests/republishing/server-initial/StdbModule.csproj
index 3d6a7699986..39a728ccd19 100644
--- a/sdks/csharp/examples~/regression-tests/republishing/server-initial/StdbModule.csproj
+++ b/sdks/csharp/examples~/regression-tests/republishing/server-initial/StdbModule.csproj
@@ -7,8 +7,46 @@
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
+  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <TargetFramework>net10.0</TargetFramework>
+    <DefineConstants>$(DefineConstants);EXPERIMENTAL_WASM_AOT</DefineConstants>
+  </PropertyGroup>
+
   <ItemGroup>
     <PackageReference Include="SpacetimeDB.Runtime" Version="1.5.0" />
   </ItemGroup>
+  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <PublishTrimmed>true</PublishTrimmed>
+    <SelfContained>true</SelfContained>
+    <WasmEnableThreads>false</WasmEnableThreads>
+  </PropertyGroup>
+
+  <Target Name="UseWasiRuntimeOverlayWithoutComponentWit"
+          Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'"
+          AfterTargets="SetupProperties"
+          BeforeTargets="LinkNativeLlvm">
+    <PropertyGroup>
+      <_OriginalIlcSdkPath>$(IlcSdkPath)</_OriginalIlcSdkPath>
+      <_WasiRuntimeOverlayDir>$(IntermediateOutputPath)native-hidden-no-wit\</_WasiRuntimeOverlayDir>
+    </PropertyGroup>
 
+    <ItemGroup>
+      <_WasiRuntimeOverlaySource Include="$(IlcFrameworkNativePath)**\*" Exclude="$(IlcFrameworkNativePath)**\*.wit" />
+    </ItemGroup>
+
+    <RemoveDir Directories="$(_WasiRuntimeOverlayDir)" />
+    <MakeDir Directories="$(_WasiRuntimeOverlayDir)" />
+    <Copy SourceFiles="@(_WasiRuntimeOverlaySource)"
+          DestinationFiles="@(_WasiRuntimeOverlaySource->'$(_WasiRuntimeOverlayDir)%(RecursiveDir)%(Filename)%(Extension)')" />
+
+    <PropertyGroup>
+      <IlcFrameworkNativePath>$(_WasiRuntimeOverlayDir)</IlcFrameworkNativePath>
+      <IlcSdkPath>$(_OriginalIlcSdkPath)</IlcSdkPath>
+    </PropertyGroup>
+  </Target>
+  
+  <ItemGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <PackageReference Include="Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" />
+    <PackageReference Include="runtime.$(NETCoreSdkPortableRuntimeIdentifier).Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" />
+  </ItemGroup>
 </Project>
diff --git a/sdks/csharp/examples~/regression-tests/republishing/server-republish/StdbModule.csproj b/sdks/csharp/examples~/regression-tests/republishing/server-republish/StdbModule.csproj
index 3d6a7699986..39a728ccd19 100644
--- a/sdks/csharp/examples~/regression-tests/republishing/server-republish/StdbModule.csproj
+++ b/sdks/csharp/examples~/regression-tests/republishing/server-republish/StdbModule.csproj
@@ -7,8 +7,46 @@
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
+  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <TargetFramework>net10.0</TargetFramework>
+    <DefineConstants>$(DefineConstants);EXPERIMENTAL_WASM_AOT</DefineConstants>
+  </PropertyGroup>
+
   <ItemGroup>
     <PackageReference Include="SpacetimeDB.Runtime" Version="1.5.0" />
   </ItemGroup>
+  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <PublishTrimmed>true</PublishTrimmed>
+    <SelfContained>true</SelfContained>
+    <WasmEnableThreads>false</WasmEnableThreads>
+  </PropertyGroup>
+
+  <Target Name="UseWasiRuntimeOverlayWithoutComponentWit"
+          Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'"
+          AfterTargets="SetupProperties"
+          BeforeTargets="LinkNativeLlvm">
+    <PropertyGroup>
+      <_OriginalIlcSdkPath>$(IlcSdkPath)</_OriginalIlcSdkPath>
+      <_WasiRuntimeOverlayDir>$(IntermediateOutputPath)native-hidden-no-wit\</_WasiRuntimeOverlayDir>
+    </PropertyGroup>
 
+    <ItemGroup>
+      <_WasiRuntimeOverlaySource Include="$(IlcFrameworkNativePath)**\*" Exclude="$(IlcFrameworkNativePath)**\*.wit" />
+    </ItemGroup>
+
+    <RemoveDir Directories="$(_WasiRuntimeOverlayDir)" />
+    <MakeDir Directories="$(_WasiRuntimeOverlayDir)" />
+    <Copy SourceFiles="@(_WasiRuntimeOverlaySource)"
+          DestinationFiles="@(_WasiRuntimeOverlaySource->'$(_WasiRuntimeOverlayDir)%(RecursiveDir)%(Filename)%(Extension)')" />
+
+    <PropertyGroup>
+      <IlcFrameworkNativePath>$(_WasiRuntimeOverlayDir)</IlcFrameworkNativePath>
+      <IlcSdkPath>$(_OriginalIlcSdkPath)</IlcSdkPath>
+    </PropertyGroup>
+  </Target>
+  
+  <ItemGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <PackageReference Include="Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" />
+    <PackageReference Include="runtime.$(NETCoreSdkPortableRuntimeIdentifier).Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" />
+  </ItemGroup>
 </Project>
diff --git a/sdks/csharp/examples~/regression-tests/server/StdbModule.csproj b/sdks/csharp/examples~/regression-tests/server/StdbModule.csproj
index af5dc63af32..4d0b06b166f 100644
--- a/sdks/csharp/examples~/regression-tests/server/StdbModule.csproj
+++ b/sdks/csharp/examples~/regression-tests/server/StdbModule.csproj
@@ -7,8 +7,46 @@
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
+  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <TargetFramework>net10.0</TargetFramework>
+    <DefineConstants>$(DefineConstants);EXPERIMENTAL_WASM_AOT</DefineConstants>
+  </PropertyGroup>
+
   <ItemGroup>
     <PackageReference Include="SpacetimeDB.Runtime" Version="2.1.*" />
   </ItemGroup>
+  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <PublishTrimmed>true</PublishTrimmed>
+    <SelfContained>true</SelfContained>
+    <WasmEnableThreads>false</WasmEnableThreads>
+  </PropertyGroup>
+
+  <Target Name="UseWasiRuntimeOverlayWithoutComponentWit"
+          Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'"
+          AfterTargets="SetupProperties"
+          BeforeTargets="LinkNativeLlvm">
+    <PropertyGroup>
+      <_OriginalIlcSdkPath>$(IlcSdkPath)</_OriginalIlcSdkPath>
+      <_WasiRuntimeOverlayDir>$(IntermediateOutputPath)native-hidden-no-wit\</_WasiRuntimeOverlayDir>
+    </PropertyGroup>
 
+    <ItemGroup>
+      <_WasiRuntimeOverlaySource Include="$(IlcFrameworkNativePath)**\*" Exclude="$(IlcFrameworkNativePath)**\*.wit" />
+    </ItemGroup>
+
+    <RemoveDir Directories="$(_WasiRuntimeOverlayDir)" />
+    <MakeDir Directories="$(_WasiRuntimeOverlayDir)" />
+    <Copy SourceFiles="@(_WasiRuntimeOverlaySource)"
+          DestinationFiles="@(_WasiRuntimeOverlaySource->'$(_WasiRuntimeOverlayDir)%(RecursiveDir)%(Filename)%(Extension)')" />
+
+    <PropertyGroup>
+      <IlcFrameworkNativePath>$(_WasiRuntimeOverlayDir)</IlcFrameworkNativePath>
+      <IlcSdkPath>$(_OriginalIlcSdkPath)</IlcSdkPath>
+    </PropertyGroup>
+  </Target>
+  
+  <ItemGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <PackageReference Include="Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" />
+    <PackageReference Include="runtime.$(NETCoreSdkPortableRuntimeIdentifier).Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" />
+  </ItemGroup>
 </Project>

From 2351acb68494ce1de15033e8c1dcba8b436ad525 Mon Sep 17 00:00:00 2001
From: rekhoff <r.ekhoff@clockworklabs.io>
Date: Tue, 28 Apr 2026 17:22:41 -0700
Subject: [PATCH 2/8] Add support for .NET 8 JIT, .NET AOT and .NET 10 AOT in
 the same NuGet package

---
 .../BSATN.Runtime/BSATN.Runtime.csproj        |   7 +-
 .../bindings-csharp/Runtime/Internal/FFI.cs   |   2 +-
 crates/bindings-csharp/Runtime/Runtime.csproj |   9 +-
 .../Runtime/build/SpacetimeDB.Runtime.props   |   3 +
 .../Runtime/build/SpacetimeDB.Runtime.targets |  38 ++-
 crates/cli/src/subcommands/init.rs            | 267 +++++++++++++-----
 crates/cli/src/tasks/csharp.rs                | 117 +++++---
 .../core/src/host/wasmtime/wasmtime_module.rs |  10 +
 .../tests/smoketests/csharp_aot_module.rs     |  62 ++--
 .../00100-cli-reference.md                    |   5 +-
 global.json                                   |   2 +-
 modules/Directory.Build.props                 |   1 +
 12 files changed, 375 insertions(+), 148 deletions(-)

diff --git a/crates/bindings-csharp/BSATN.Runtime/BSATN.Runtime.csproj b/crates/bindings-csharp/BSATN.Runtime/BSATN.Runtime.csproj
index 4f6afaa8dd6..3bbfd33a32d 100644
--- a/crates/bindings-csharp/BSATN.Runtime/BSATN.Runtime.csproj
+++ b/crates/bindings-csharp/BSATN.Runtime/BSATN.Runtime.csproj
@@ -9,17 +9,12 @@
 
   <PropertyGroup>
     <!-- Note: the binary produced by this package is used in Unity too, which is limited to .NET Standard 2.1. -->
-    <TargetFrameworks>netstandard2.1;net8.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.1;net8.0;net10.0</TargetFrameworks>
     <RootNamespace>SpacetimeDB</RootNamespace>
     <!-- You can enable this when debugging codegen problems. Outputs in obj/debug/[version]/generated. -->
     <!-- <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles> -->
   </PropertyGroup>
 
-  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
-    <TargetFrameworks>netstandard2.1;net10.0</TargetFrameworks>
-    <DefineConstants>$(DefineConstants);EXPERIMENTAL_WASM_AOT</DefineConstants>
-  </PropertyGroup>
-
   <ItemGroup>
     <!-- We want to build BSATN.Codegen both to include it in our NuGet package but also we want it to transform [SpacetimeDB.Type] usages in BSATN.Runtime code itself. -->
     <ProjectReference
diff --git a/crates/bindings-csharp/Runtime/Internal/FFI.cs b/crates/bindings-csharp/Runtime/Internal/FFI.cs
index 0fb30bb1a16..3fe39825483 100644
--- a/crates/bindings-csharp/Runtime/Internal/FFI.cs
+++ b/crates/bindings-csharp/Runtime/Internal/FFI.cs
@@ -2,7 +2,7 @@ namespace SpacetimeDB.Internal;
 
 using System.Runtime.InteropServices;
 using System.Runtime.InteropServices.Marshalling;
-#if EXPERIMENTAL_WASM_AOT
+#if EXPERIMENTAL_WASM_AOT && NET10_0_OR_GREATER
 using WasmImportLinkageAttribute = System.Runtime.InteropServices.WasmImportLinkageAttribute;
 #else
 [AttributeUsage(AttributeTargets.Method, AllowMultiple = false)]
diff --git a/crates/bindings-csharp/Runtime/Runtime.csproj b/crates/bindings-csharp/Runtime/Runtime.csproj
index af84834c7b2..112f5d4fcc8 100644
--- a/crates/bindings-csharp/Runtime/Runtime.csproj
+++ b/crates/bindings-csharp/Runtime/Runtime.csproj
@@ -8,15 +8,14 @@
   </PropertyGroup>
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFrameworks>net8.0;net10.0</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <RootNamespace>SpacetimeDB</RootNamespace>
     <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
-    <RestoreAdditionalProjectSources Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-experimental/nuget/v3/index.json;$(RestoreAdditionalProjectSources)</RestoreAdditionalProjectSources>
+    <RestoreAdditionalProjectSources>https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-experimental/nuget/v3/index.json;$(RestoreAdditionalProjectSources)</RestoreAdditionalProjectSources>
   </PropertyGroup>
 
-  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
-    <TargetFramework>net10.0</TargetFramework>
+  <PropertyGroup Condition="'$(TargetFramework)' == 'net10.0'">
     <DefineConstants>$(DefineConstants);EXPERIMENTAL_WASM_AOT</DefineConstants>
   </PropertyGroup>
 
@@ -32,7 +31,7 @@
   </ItemGroup>
 
   <!-- These must be explicit package dependencies so NuGet consumers can resolve the LLVM toolchain. -->
-  <ItemGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+  <ItemGroup Condition="'$(TargetFramework)' == 'net10.0'">
     <PackageReference Include="Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" IncludeAssets="All" />
     <PackageReference Include="runtime.$(NETCoreSdkPortableRuntimeIdentifier).Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" IncludeAssets="All" />
   </ItemGroup>
diff --git a/crates/bindings-csharp/Runtime/build/SpacetimeDB.Runtime.props b/crates/bindings-csharp/Runtime/build/SpacetimeDB.Runtime.props
index 58ccaa0de6e..c34516d38dd 100644
--- a/crates/bindings-csharp/Runtime/build/SpacetimeDB.Runtime.props
+++ b/crates/bindings-csharp/Runtime/build/SpacetimeDB.Runtime.props
@@ -15,6 +15,9 @@
     <DefineConstants>$(DefineConstants);EXPERIMENTAL_WASM_AOT</DefineConstants>
     <MSBuildEnableWorkloadResolver>false</MSBuildEnableWorkloadResolver>
     <UseAppHost>false</UseAppHost>
+    <PublishTrimmed>true</PublishTrimmed>
+    <SelfContained>true</SelfContained>
+    <WasmEnableThreads>false</WasmEnableThreads>
     <SpacetimeNamespace>spacetime_10.0</SpacetimeNamespace>
     <RestoreAdditionalProjectSources>https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-experimental/nuget/v3/index.json</RestoreAdditionalProjectSources>
   </PropertyGroup>
diff --git a/crates/bindings-csharp/Runtime/build/SpacetimeDB.Runtime.targets b/crates/bindings-csharp/Runtime/build/SpacetimeDB.Runtime.targets
index ec8fac8b3b7..c97678557bc 100644
--- a/crates/bindings-csharp/Runtime/build/SpacetimeDB.Runtime.targets
+++ b/crates/bindings-csharp/Runtime/build/SpacetimeDB.Runtime.targets
@@ -4,6 +4,12 @@
       Project="$(PkgMicrosoft_DotNet_ILCompiler_LLVM)\build\Microsoft.DotNet.ILCompiler.LLVM.targets"
       Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1' and '$(ILCompilerTargetsPath)' == '' and '$(PkgMicrosoft_DotNet_ILCompiler_LLVM)' != '' and Exists('$(PkgMicrosoft_DotNet_ILCompiler_LLVM)\build\Microsoft.DotNet.ILCompiler.LLVM.targets')" />
 
+  <!-- Override IlcLlvmTarget AFTER the ILCompiler.LLVM.targets import (which defaults to wasip2).
+       SpacetimeDB's host only supports WASI Preview 1 (wasip1). -->
+  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
+    <IlcLlvmTarget>wasm32-unknown-wasip1</IlcLlvmTarget>
+  </PropertyGroup>
+
   <ItemGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
     <NativeLibrary Include="$(MSBuildThisFileDirectory)..\bindings.c" />
     <UnmanagedEntryPointsAssembly Include="SpacetimeDB.Runtime" />
@@ -46,6 +52,9 @@
     <WasmImport Include="spacetime_10.4!datastore_index_scan_point_bsatn" />
     <WasmImport Include="spacetime_10.4!datastore_delete_by_index_scan_point_bsatn" />
 
+    <!-- spacetime_10.5 imports -->
+    <WasmImport Include="spacetime_10.5!datastore_clear" />
+
     <CustomLinkerArg Include="-DEXPERIMENTAL_WASM_AOT" />
   </ItemGroup>
 
@@ -54,11 +63,38 @@
     <_WasmNativeFileForLinking Include="@(NativeFileReference)" />
   </ItemGroup>
 
+  <!-- Strip .wit files from the WASI runtime overlay to prevent NativeAOT-LLVM from
+       generating WebAssembly Component Model exports (wasip2). SpacetimeDB's host only
+       supports WASI Preview 1 (wasip1), so component-model exports cause failures. -->
+  <Target Name="UseWasiRuntimeOverlayWithoutComponentWit"
+          Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'"
+          AfterTargets="SetupProperties"
+          BeforeTargets="LinkNativeLlvm">
+    <PropertyGroup>
+      <_OriginalIlcSdkPath>$(IlcSdkPath)</_OriginalIlcSdkPath>
+      <_WasiRuntimeOverlayDir>$(IntermediateOutputPath)native-hidden-no-wit\</_WasiRuntimeOverlayDir>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <_WasiRuntimeOverlaySource Include="$(IlcFrameworkNativePath)**\*" Exclude="$(IlcFrameworkNativePath)**\*.wit" />
+    </ItemGroup>
+
+    <RemoveDir Directories="$(_WasiRuntimeOverlayDir)" />
+    <MakeDir Directories="$(_WasiRuntimeOverlayDir)" />
+    <Copy SourceFiles="@(_WasiRuntimeOverlaySource)"
+          DestinationFiles="@(_WasiRuntimeOverlaySource->'$(_WasiRuntimeOverlayDir)%(RecursiveDir)%(Filename)%(Extension)')" />
+
+    <PropertyGroup>
+      <IlcFrameworkNativePath>$(_WasiRuntimeOverlayDir)</IlcFrameworkNativePath>
+      <IlcSdkPath>$(_OriginalIlcSdkPath)</IlcSdkPath>
+    </PropertyGroup>
+  </Target>
+
   <!-- Auto-download WASI SDK on the first run. -->
   <!-- Adapted from https://github.com/dotnet/dotnet-wasi-sdk/blob/2dbb00c779180873d3ed985e59e431f56404d8da/src/Wasi.Sdk/build/Wasi.Sdk.targets#L245-L262 -->
   <!-- Executes before the errors in https://github.com/dotnet/runtime/blob/57fd56a99d4c97ac2f95fe84640f2a3f653f4dd7/src/mono/wasi/build/WasiApp.Native.targets#L41-L50. -->
   <!-- TODO: remove when https://github.com/dotnet/runtime/issues/82788 is resolved. -->
-  <Target Name="ObtainWasiSdk" BeforeTargets="_SetupWasiSdk;CheckWasmSdks">
+  <Target Name="ObtainWasiSdk" BeforeTargets="_SetupWasiSdk;CheckWasmSdks;_InitializeWasiSdk">
     <PropertyGroup>
       <WasiSdkVersion>29</WasiSdkVersion>
 
diff --git a/crates/cli/src/subcommands/init.rs b/crates/cli/src/subcommands/init.rs
index 90a5e9ecf76..bf6270e152c 100644
--- a/crates/cli/src/subcommands/init.rs
+++ b/crates/cli/src/subcommands/init.rs
@@ -134,6 +134,8 @@ pub struct InitOptions {
     pub skip_next_steps: bool,
     /// When true, configure C# projects for NativeAOT-LLVM compilation.
     pub native_aot: bool,
+    /// Explicit .NET major version override (e.g. 8 or 10). When set, skips auto-detection.
+    pub dotnet_version: Option<u8>,
 }
 
 impl InitOptions {
@@ -150,6 +152,9 @@ impl InitOptions {
             non_interactive: args.get_flag("non-interactive"),
             skip_next_steps: false,
             native_aot: args.get_flag("native-aot"),
+            dotnet_version: args
+                .get_one::<String>("dotnet-version")
+                .and_then(|s| s.parse::<u8>().ok()),
         }
     }
 }
@@ -199,6 +204,12 @@ pub fn cli() -> clap::Command {
                 .action(clap::ArgAction::SetTrue)
                 .help("Configure C# project for NativeAOT-LLVM compilation (experimental, Windows only)"),
         )
+        .arg(
+            Arg::new("dotnet-version")
+                .long("dotnet-version")
+                .value_name("VERSION")
+                .help("Target .NET SDK major version for C# projects (e.g. 8 or 10). Auto-detected when omitted."),
+        )
 }
 
 pub async fn fetch_templates_list() -> anyhow::Result<Vec<TemplateDefinition>> {
@@ -530,21 +541,42 @@ pub async fn exec_with_options(config: &mut Config, options: &InitOptions) -> an
 
     template_config.use_local = use_local;
 
+    // For C# projects, resolve the target .NET version before scaffolding.
+    // This may prompt the user interactively if multiple SDKs are installed.
+    let dotnet_major = if template_config.server_lang == Some(ServerLanguage::Csharp) {
+        Some(resolve_dotnet_major(options, is_interactive)?)
+    } else {
+        None
+    };
+
     ensure_empty_directory(
         &template_config.project_name,
         &template_config.project_path,
         is_server_only,
     )?;
-    init_from_template(&template_config, &template_config.project_path, is_server_only).await?;
-
-    // Add NativeAOT-LLVM package references to C# projects if --native-aot was specified
-    if options.native_aot && template_config.server_lang == Some(ServerLanguage::Csharp) {
+    init_from_template(
+        &template_config,
+        &template_config.project_path,
+        is_server_only,
+        dotnet_major,
+    )
+    .await?;
+
+    // Add NativeAOT-LLVM project configuration for C# projects when:
+    //   - --native-aot was explicitly specified, OR
+    //   - .NET 10 was selected/detected as the target
+    let needs_native_aot = if template_config.server_lang == Some(ServerLanguage::Csharp) {
+        options.native_aot || dotnet_major == Some(10)
+    } else {
+        false
+    };
+    if needs_native_aot {
         let server_dir = template_config.project_path.join("spacetimedb");
-        add_native_aot_packages_to_csproj(&server_dir)?;
+        add_native_aot_packages_to_csproj(&server_dir, dotnet_major)?;
     }
 
     let default_server = config.default_server_name().unwrap_or("maincloud");
-    if let Some(path) = create_default_spacetime_config_if_missing(&project_path, options.native_aot, default_server)? {
+    if let Some(path) = create_default_spacetime_config_if_missing(&project_path, needs_native_aot, default_server)? {
         println!("{} Created {}", "✓".green(), path.display());
     }
 
@@ -1331,13 +1363,14 @@ pub async fn init_from_template(
     config: &TemplateConfig,
     project_path: &Path,
     is_server_only: bool,
+    dotnet_major: Option<u8>,
 ) -> anyhow::Result<()> {
     println!("{}", "Initializing project from template...".cyan());
 
     match config.template_type {
-        TemplateType::Builtin => init_builtin(config, project_path, is_server_only)?,
+        TemplateType::Builtin => init_builtin(config, project_path, is_server_only, dotnet_major)?,
         TemplateType::GitHub => init_github_template(config, project_path, is_server_only)?,
-        TemplateType::Empty => init_empty(config, project_path)?,
+        TemplateType::Empty => init_empty(config, project_path, dotnet_major)?,
     }
 
     // Install AI assistant rules for multiple editors/tools
@@ -1348,7 +1381,12 @@ pub async fn init_from_template(
     Ok(())
 }
 
-fn init_builtin(config: &TemplateConfig, project_path: &Path, is_server_only: bool) -> anyhow::Result<()> {
+fn init_builtin(
+    config: &TemplateConfig,
+    project_path: &Path,
+    is_server_only: bool,
+    dotnet_major: Option<u8>,
+) -> anyhow::Result<()> {
     let template_def = config
         .template_def
         .as_ref()
@@ -1417,6 +1455,16 @@ fn init_builtin(config: &TemplateConfig, project_path: &Path, is_server_only: bo
         None => {}
     }
 
+    // For C# projects targeting .NET 10, override the template global.json
+    // (the embedded template ships with 8.0.100 which is wrong for .NET 10).
+    if config.server_lang == Some(ServerLanguage::Csharp) && dotnet_major == Some(10) {
+        let global_json_path = server_dir.join("global.json");
+        let net10_global_json =
+            "{\n  \"sdk\": {\n    \"version\": \"10.0.100\",\n    \"rollForward\": \"latestMinor\"\n  }\n}\n";
+        std::fs::write(&global_json_path, net10_global_json)?;
+        println!("Updating global.json to use .NET 10 (NativeAOT-LLVM).");
+    }
+
     Ok(())
 }
 
@@ -1454,7 +1502,7 @@ fn init_github_template(config: &TemplateConfig, project_path: &Path, is_server_
     Ok(())
 }
 
-fn init_empty(config: &TemplateConfig, project_path: &Path) -> anyhow::Result<()> {
+fn init_empty(config: &TemplateConfig, project_path: &Path, dotnet_major: Option<u8>) -> anyhow::Result<()> {
     match config.server_lang {
         Some(ServerLanguage::Rust) => {
             println!("Setting up Rust server...");
@@ -1464,7 +1512,7 @@ fn init_empty(config: &TemplateConfig, project_path: &Path) -> anyhow::Result<()
         Some(ServerLanguage::Csharp) => {
             println!("Setting up C# server...");
             let server_dir = project_path.join("spacetimedb");
-            init_empty_csharp_server(&server_dir, &config.project_name)?;
+            init_empty_csharp_server(&server_dir, &config.project_name, dotnet_major)?;
         }
         Some(ServerLanguage::TypeScript) => {
             println!("Setting up TypeScript server...");
@@ -1488,8 +1536,8 @@ fn init_empty_rust_server(server_dir: &Path, project_name: &str) -> anyhow::Resu
     Ok(())
 }
 
-fn init_empty_csharp_server(server_dir: &Path, _project_name: &str) -> anyhow::Result<()> {
-    init_csharp_project(server_dir)
+fn init_empty_csharp_server(server_dir: &Path, _project_name: &str, dotnet_major: Option<u8>) -> anyhow::Result<()> {
+    init_csharp_project(server_dir, dotnet_major)
 }
 
 fn init_empty_typescript_server(server_dir: &Path, project_name: &str) -> anyhow::Result<()> {
@@ -1600,6 +1648,83 @@ fn check_for_cargo() -> bool {
     false
 }
 
+/// Returns the set of major .NET SDK versions installed (e.g. {8, 10}).
+fn detect_installed_dotnet_majors() -> Vec<u8> {
+    let output = duct::cmd!("dotnet", "--list-sdks").read().unwrap_or_default();
+    let mut majors: Vec<u8> = output
+        .lines()
+        .filter_map(|line| {
+            // Each line looks like: "8.0.100 [C:\Program Files\dotnet\sdk]"
+            let version_str = line.split_whitespace().next()?;
+            crate::tasks::csharp::parse_major_version(version_str)
+        })
+        .collect();
+    majors.sort();
+    majors.dedup();
+    majors
+}
+
+/// Determine the target .NET major version for a C# project.
+///
+/// Resolution order:
+///   1. Explicit `--dotnet-version` flag
+///   2. Interactive prompt (if multiple supported versions are installed)
+///   3. Auto-detect from `dotnet --version` (single supported version or non-interactive)
+fn resolve_dotnet_major(options: &InitOptions, is_interactive: bool) -> anyhow::Result<u8> {
+    // 1. Explicit flag takes priority.
+    if let Some(v) = options.dotnet_version {
+        match v {
+            8 | 10 => return Ok(v),
+            _ => anyhow::bail!("Unsupported --dotnet-version {v}. Supported values: 8, 10."),
+        }
+    }
+
+    // --native-aot is for .NET 8 AOT builds (NativeAOT-LLVM with net8.0 TFM).
+    // .NET 10 always uses NativeAOT-LLVM, no flag needed.
+    if options.native_aot {
+        return Ok(8);
+    }
+
+    let installed = detect_installed_dotnet_majors();
+    let supported: Vec<u8> = installed.iter().copied().filter(|&v| v == 8 || v == 10).collect();
+
+    match supported.len() {
+        0 => {
+            // Fall back to whatever `dotnet --version` reports.
+            let ver = duct::cmd!("dotnet", "--version").read().unwrap_or_default();
+            crate::tasks::csharp::parse_major_version(&ver).ok_or_else(|| {
+                anyhow::anyhow!("Could not detect .NET SDK version. Please install .NET SDK 8.0 or 10.0.")
+            })
+        }
+        1 => Ok(supported[0]),
+        _ => {
+            // Multiple supported versions — prompt if interactive, else use highest.
+            if is_interactive {
+                let theme = ColorfulTheme::default();
+                let choices: Vec<String> = supported
+                    .iter()
+                    .map(|v| match v {
+                        8 => ".NET 8 (JIT — stable, uses wasi-experimental workload)".to_string(),
+                        10 => ".NET 10 (NativeAOT-LLVM — experimental, better performance)".to_string(),
+                        other => format!(".NET {other}"),
+                    })
+                    .collect();
+
+                let selection = Select::with_theme(&theme)
+                    .with_prompt("Multiple .NET SDKs found. Which version should this C# module target?")
+                    .items(&choices)
+                    .default(choices.len() - 1) // Default to highest (typically .NET 10)
+                    .interact()?;
+
+                Ok(supported[selection])
+            } else {
+                // Non-interactive: use the highest supported version.
+                Ok(*supported.last().unwrap())
+            }
+        }
+    }
+}
+
 fn check_for_dotnet() -> bool {
     use std::fmt::Write;
 
@@ -1694,6 +1819,19 @@ pub async fn exec(mut config: Config, args: &ArgMatches) -> anyhow::Result<PathB
         );
     }
 
+    // Validate that --dotnet-version is only used with C# projects
+    if let Some(v) = options.dotnet_version {
+        if let Some(lang) = server_lang
+            && lang.to_lowercase() != "csharp"
+            && lang.to_lowercase() != "c#"
+        {
+            anyhow::bail!("--dotnet-version is only supported for C# projects (--lang csharp)");
+        }
+        if v != 8 && v != 10 {
+            anyhow::bail!("Unsupported --dotnet-version {v}. Supported values: 8, 10.");
+        }
+    }
+
     if !is_interactive {
         // In non-interactive mode, validate all required args are present
         if project_name_arg.is_none() {
@@ -1731,7 +1869,20 @@ pub fn init_rust_project(project_path: &Path) -> anyhow::Result<()> {
     Ok(())
 }
 
-pub fn init_csharp_project(project_path: &Path) -> anyhow::Result<()> {
+pub fn init_csharp_project(project_path: &Path, dotnet_major: Option<u8>) -> anyhow::Result<()> {
+    check_for_dotnet();
+    check_for_git();
+
+    let global_json = match dotnet_major {
+        Some(10) => {
+            println!("{} Scaffolding for .NET 10 (NativeAOT-LLVM).", "ℹ".blue(),);
+            "{\n  \"sdk\": {\n    \"version\": \"10.0.100\",\n    \"rollForward\": \"latestMinor\"\n  }\n}\n"
+        }
+        _ => {
+            include_str!("../../../../templates/basic-cs/spacetimedb/global.json")
+        }
+    };
+
     let export_files = vec![
         (
             include_str!("../../../../templates/basic-cs/spacetimedb/StdbModule.csproj"),
@@ -1741,15 +1892,9 @@ pub fn init_csharp_project(project_path: &Path) -> anyhow::Result<()> {
             include_str!("../../../../templates/basic-cs/spacetimedb/Lib.cs"),
             "Lib.cs",
         ),
-        (
-            include_str!("../../../../templates/basic-cs/spacetimedb/global.json"),
-            "global.json",
-        ),
+        (global_json, "global.json"),
     ];
 
-    check_for_dotnet();
-    check_for_git();
-
     for data_file in export_files {
         let path = project_path.join(data_file.1);
         create_directory(path.parent().unwrap())?;
@@ -1760,8 +1905,18 @@ pub fn init_csharp_project(project_path: &Path) -> anyhow::Result<()> {
 }
 
 /// Adds NativeAOT-LLVM project configuration to an existing C# .csproj file and creates NuGet.Config.
-/// This is called when `--native-aot` is specified during `spacetime init`.
-fn add_native_aot_packages_to_csproj(project_path: &Path) -> anyhow::Result<()> {
+///
+/// The configuration differs depending on the target .NET version:
+///
+/// **.NET 8 AOT** (`--native-aot`): Keeps `net8.0` TFM and adds explicit ILCompiler.LLVM 8.0.0-*
+/// package references, gated on `EXPERIMENTAL_WASM_AOT=1`.
+///
+/// **.NET 10 AOT**: Replaces the TFM with `net10.0` directly (no conditional needed since the
+/// project is definitively targeting .NET 10). ILCompiler.LLVM refs are provided transitively
+/// by the SpacetimeDB.Runtime NuGet package.
+///
+/// Both paths need a NuGet.Config with the dotnet-experimental feed for ILCompiler.LLVM resolution.
+fn add_native_aot_packages_to_csproj(project_path: &Path, dotnet_major: Option<u8>) -> anyhow::Result<()> {
     let csproj_path = project_path.join("StdbModule.csproj");
     if !csproj_path.exists() {
         anyhow::bail!("Could not find StdbModule.csproj at {}", csproj_path.display());
@@ -1769,55 +1924,27 @@ fn add_native_aot_packages_to_csproj(project_path: &Path) -> anyhow::Result<()>
 
     let content = std::fs::read_to_string(&csproj_path)?;
 
-    // The NativeAOT-LLVM configuration to add
-    let native_aot_config = r#"
-  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
-    <TargetFramework>net10.0</TargetFramework>
-    <DefineConstants>$(DefineConstants);EXPERIMENTAL_WASM_AOT</DefineConstants>
-  </PropertyGroup>
-
-  <PropertyGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
-    <PublishTrimmed>true</PublishTrimmed>
-    <SelfContained>true</SelfContained>
-    <WasmEnableThreads>false</WasmEnableThreads>
-  </PropertyGroup>
-
-  <Target Name="UseWasiRuntimeOverlayWithoutComponentWit"
-          Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'"
-          AfterTargets="SetupProperties"
-          BeforeTargets="LinkNativeLlvm">
-    <PropertyGroup>
-      <_OriginalIlcSdkPath>$(IlcSdkPath)</_OriginalIlcSdkPath>
-      <_WasiRuntimeOverlayDir>$(IntermediateOutputPath)native-hidden-no-wit\</_WasiRuntimeOverlayDir>
-    </PropertyGroup>
-
-    <ItemGroup>
-      <_WasiRuntimeOverlaySource Include="$(IlcFrameworkNativePath)**\*" Exclude="$(IlcFrameworkNativePath)**\*.wit" />
-    </ItemGroup>
-
-    <RemoveDir Directories="$(_WasiRuntimeOverlayDir)" />
-    <MakeDir Directories="$(_WasiRuntimeOverlayDir)" />
-    <Copy SourceFiles="@(_WasiRuntimeOverlaySource)"
-          DestinationFiles="@(_WasiRuntimeOverlaySource->'$(_WasiRuntimeOverlayDir)%(RecursiveDir)%(Filename)%(Extension)')" />
-
-    <PropertyGroup>
-      <IlcFrameworkNativePath>$(_WasiRuntimeOverlayDir)</IlcFrameworkNativePath>
-      <IlcSdkPath>$(_OriginalIlcSdkPath)</IlcSdkPath>
-    </PropertyGroup>
-  </Target>
-
+    let new_content = if dotnet_major == Some(8) {
+        // .NET 8 AOT: keep net8.0 TFM, add explicit ILCompiler.LLVM package references.
+        let native_aot_config = r#"
   <ItemGroup Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">
-    <PackageReference Include="Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" />
-    <PackageReference Include="runtime.$(NETCoreSdkPortableRuntimeIdentifier).Microsoft.DotNet.ILCompiler.LLVM" Version="10.0.0-*" />
+    <PackageReference Include="Microsoft.DotNet.ILCompiler.LLVM" Version="8.0.0-*" />
+    <PackageReference Include="runtime.$(NETCoreSdkPortableRuntimeIdentifier).Microsoft.DotNet.ILCompiler.LLVM" Version="8.0.0-*" />
   </ItemGroup>
 "#;
-
-    // Insert the NativeAOT config before the closing </Project> tag
-    let new_content = if let Some(pos) = content.rfind("</Project>") {
-        let (before, after) = content.split_at(pos);
-        format!("{}{}{}", before.trim_end(), native_aot_config, after)
+        if let Some(pos) = content.rfind("</Project>") {
+            let (before, after) = content.split_at(pos);
+            format!("{}{}{}", before.trim_end(), native_aot_config, after)
+        } else {
+            anyhow::bail!("Invalid .csproj file: missing </Project> tag");
+        }
     } else {
-        anyhow::bail!("Invalid .csproj file: missing </Project> tag");
+        // .NET 10 AOT: directly set TFM to net10.0 (no conditional needed).
+        // ILCompiler.LLVM comes transitively via the SpacetimeDB.Runtime NuGet package.
+        content.replace(
+            "<TargetFramework>net8.0</TargetFramework>",
+            "<TargetFramework>net10.0</TargetFramework>",
+        )
     };
 
     std::fs::write(&csproj_path, new_content)?;
@@ -1827,7 +1954,7 @@ fn add_native_aot_packages_to_csproj(project_path: &Path) -> anyhow::Result<()>
         csproj_path.display()
     );
 
-    // Create NuGet.Config with the dotnet-experimental feed required for NativeAOT-LLVM packages
+    // Create NuGet.Config with the dotnet-experimental feed required for ILCompiler.LLVM packages
     let nuget_config_path = project_path.join("NuGet.Config");
     let nuget_config_content = r#"<?xml version="1.0" encoding="utf-8"?>
 <configuration>
@@ -1918,7 +2045,7 @@ pub async fn exec_init_rust(args: &ArgMatches) -> anyhow::Result<()> {
 
 pub async fn exec_init_csharp(args: &ArgMatches) -> anyhow::Result<()> {
     let project_path = args.get_one::<PathBuf>("project-path").unwrap();
-    init_csharp_project(project_path)?;
+    init_csharp_project(project_path, None)?;
 
     println!(
         "{}",
diff --git a/crates/cli/src/tasks/csharp.rs b/crates/cli/src/tasks/csharp.rs
index cfac60422ea..dad46f2b210 100644
--- a/crates/cli/src/tasks/csharp.rs
+++ b/crates/cli/src/tasks/csharp.rs
@@ -4,10 +4,20 @@ use std::ffi::OsString;
 use std::fs;
 use std::path::{Path, PathBuf};
 
-fn parse_major_version(version: &str) -> Option<u8> {
+pub(crate) fn parse_major_version(version: &str) -> Option<u8> {
     version.split('.').next()?.parse::<u8>().ok()
 }
 
+/// Describes which C# build path to use.
+enum CsharpBuildPath {
+    /// .NET 8 JIT via the `wasi-experimental` workload (Mono WASM).
+    Net8Jit,
+    /// .NET 8 NativeAOT-LLVM (opt-in via `--native-aot`).
+    Net8Aot,
+    /// .NET 10 NativeAOT-LLVM (auto-detected, only available path for .NET 10).
+    Net10Aot,
+}
+
 pub(crate) fn build_csharp(project_path: &Path, build_debug: bool) -> anyhow::Result<PathBuf> {
     // All `dotnet` commands must execute in the project directory, otherwise
     // global.json won't have any effect and wrong .NET SDK might be picked.
@@ -17,17 +27,56 @@ pub(crate) fn build_csharp(project_path: &Path, build_debug: bool) -> anyhow::Re
         };
     }
 
-    let experimental_wasm_aot = std::env::var_os("EXPERIMENTAL_WASM_AOT").is_some_and(|v| v == "1");
+    let native_aot_flag = std::env::var_os("EXPERIMENTAL_WASM_AOT").is_some_and(|v| v == "1");
+
+    // Detect the .NET SDK version available at the project path (respects global.json).
+    let dotnet_version_str = match dotnet!("--version").read() {
+        Ok(v) => v,
+        Err(error) if error.kind() == std::io::ErrorKind::NotFound => {
+            anyhow::bail!("dotnet not found in PATH. Please install .NET SDK 8.0 or 10.0.")
+        }
+        Err(error) => anyhow::bail!("{error}"),
+    };
+    let dotnet_major = parse_major_version(&dotnet_version_str);
+
+    // Determine the build path based on SDK version and --native-aot flag.
+    let build_path = match (dotnet_major, native_aot_flag) {
+        // .NET 10: always use NativeAOT-LLVM, no flag needed.
+        (Some(10), _) => {
+            if native_aot_flag {
+                println!("Note: --native-aot is not needed with .NET 10 (NativeAOT-LLVM is used automatically).");
+            }
+            CsharpBuildPath::Net10Aot
+        }
+        // .NET 8 with --native-aot: use NativeAOT-LLVM with .NET 8 ILCompiler packages.
+        (Some(8), true) => CsharpBuildPath::Net8Aot,
+        // .NET 8 without flag: use the existing wasi-experimental JIT path.
+        (Some(8), false) => CsharpBuildPath::Net8Jit,
+        // Unsupported version.
+        _ => {
+            anyhow::bail!(
+                "Unsupported .NET SDK version: {dotnet_version_str}. SpacetimeDB requires .NET SDK 8.0 or 10.0.\n\
+                 If you have multiple versions installed, configure your project using \
+                 https://learn.microsoft.com/en-us/dotnet/core/tools/global-json."
+            );
+        }
+    };
 
-    if experimental_wasm_aot {
-        let version = dotnet!("--version").read().unwrap_or_default();
-        if parse_major_version(&version) != Some(10) {
-            anyhow::bail!(concat!(
-                ".NET SDK 10.0 is required for NativeAOT-LLVM C# builds, but found {version}.\n",
-                "If you have multiple versions of .NET SDK installed, configure your project using https://learn.microsoft.com/en-us/dotnet/core/tools/global-json."
-            ));
+    // For NativeAOT paths, ensure EXPERIMENTAL_WASM_AOT is set in the environment so MSBuild
+    // conditionals in .csproj/.props/.targets files activate correctly.
+    match &build_path {
+        CsharpBuildPath::Net8Aot | CsharpBuildPath::Net10Aot => {
+            // SAFETY: We are single-threaded at this point and no other code is reading
+            // this environment variable concurrently.
+            unsafe {
+                std::env::set_var("EXPERIMENTAL_WASM_AOT", "1");
+            }
         }
-    } else {
+        CsharpBuildPath::Net8Jit => {}
+    }
+
+    // For the JIT path, ensure the wasi-experimental workload is installed.
+    if matches!(build_path, CsharpBuildPath::Net8Jit) {
         // Check if the `wasi-experimental` workload is installed. Unfortunately, we
         // have to do this by inspecting the human-readable output. There is a
         // hidden `--machine-readable` flag but it also mixes in human-readable
@@ -35,18 +84,6 @@ pub(crate) fn build_csharp(project_path: &Path, build_debug: bool) -> anyhow::Re
         match dotnet!("workload", "list").read() {
             Ok(workloads) if workloads.contains("wasi-experimental") => {}
             Ok(_) => {
-                // If wasi-experimental is not found, first check if we're running
-                // on .NET SDK 8.0. We can't even install that workload on older
-                // versions, and we don't support .NET 9.0 yet, so this helps to
-                // provide a nicer message than "Workload ID wasi-experimental is not recognized.".
-                let version = dotnet!("--version").read().unwrap_or_default();
-                if parse_major_version(&version) != Some(8) {
-                    anyhow::bail!(concat!(
-                        ".NET SDK 8.0 is required, but found {version}.\n",
-                        "If you have multiple versions of .NET SDK installed, configure your project using https://learn.microsoft.com/en-us/dotnet/core/tools/global-json."
-                    ));
-                }
-
                 // Finally, try to install the workload ourselves. On some systems
                 // this might require elevated privileges, so print a nice error
                 // message if it fails.
@@ -63,9 +100,6 @@ pub(crate) fn build_csharp(project_path: &Path, build_debug: bool) -> anyhow::Re
                     "You might need to install it manually by running `dotnet workload install wasi-experimental` with privileged rights."
                 ))?;
             }
-            Err(error) if error.kind() == std::io::ErrorKind::NotFound => {
-                anyhow::bail!("dotnet not found in PATH. Please install .NET SDK 8.0.")
-            }
             Err(error) => anyhow::bail!("{error}"),
         };
     }
@@ -80,26 +114,21 @@ pub(crate) fn build_csharp(project_path: &Path, build_debug: bool) -> anyhow::Re
         )
     })?;
 
-    if experimental_wasm_aot {
-        dotnet!(
-            "publish",
-            "-c",
-            config_name,
-            "-v",
-            "quiet",
-            "/p:IlcLlvmTarget=wasm32-unknown-wasip1",
-            "/p:WasmEnableThreads=false"
-        )
-        .run()?;
-    } else {
-        // run dotnet publish using cmd macro
-        dotnet!("publish", "-c", config_name, "-v", "quiet").run()?;
-    }
+    // JIT and AOT builds use the same `dotnet publish` command.
+    // Build-specific configuration (TFM, AOT settings, ILCompiler packages)
+    // is handled by build_path detection and MSBuild props/targets.
+    dotnet!("publish", "-c", config_name, "-v", "quiet").run()?;
+
+    // Determine output path based on build path.
+    // Both JIT and AOT builds produce StdbModule.wasm, but in different subdirectories:
+    // - JIT (wasi-experimental): AppBundle/StdbModule.wasm
+    // - AOT (NativeAOT-LLVM): publish/StdbModule.wasm
+    let (target_framework, subdir) = match &build_path {
+        CsharpBuildPath::Net10Aot => ("net10.0", "publish"),
+        CsharpBuildPath::Net8Aot => ("net8.0", "publish"),
+        CsharpBuildPath::Net8Jit => ("net8.0", "AppBundle"),
+    };
 
-    // check if file exists
-    let subdir = if experimental_wasm_aot { "publish" } else { "AppBundle" };
-    let target_framework = if experimental_wasm_aot { "net10.0" } else { "net8.0" };
-    // TODO: This code looks for build outputs in both `bin` and `bin~` as output directories. @bfops feels like we shouldn't have to look for `bin~`, since the `~` suffix is just intended to cause Unity to ignore directories, and that shouldn't be relevant here. We do think we've seen `bin~` appear though, and it's not harmful to do the extra checks, so we're merging for now due to imminent code freeze. At some point, it would be good to figure out if we do actually see `bin~` in module directories, and where that's coming from (which could suggest a bug).
     // check for the old .NET 7 path for projects that haven't migrated yet
     let bad_output_paths = [
         project_path.join(format!("bin/{config_name}/net7.0/StdbModule.wasm")),
diff --git a/crates/core/src/host/wasmtime/wasmtime_module.rs b/crates/core/src/host/wasmtime/wasmtime_module.rs
index 0690120eb16..060bedc448b 100644
--- a/crates/core/src/host/wasmtime/wasmtime_module.rs
+++ b/crates/core/src/host/wasmtime/wasmtime_module.rs
@@ -233,6 +233,16 @@ impl module_host_actor::WasmInstancePre for WasmtimeModule {
         set_store_fuel(&mut store, FunctionBudget::DEFAULT_BUDGET.into());
         store.set_epoch_deadline(EPOCH_TICKS_PER_SECOND);
 
+        // NativeAOT-LLVM modules are WASI reactors that export `_initialize`
+        // to set up the native runtime. This must be called before any other exports.
+        // Traditional .NET 8 WASI modules export `_start` instead (which is not called here).
+        if let Ok(init) = instance.get_typed_func::<(), ()>(&mut store, "_initialize") {
+            call_sync_typed_func(&init, &mut store, ()).map_err(|err| InitializationError::RuntimeError {
+                err,
+                func: "_initialize".to_owned(),
+            })?;
+        }
+
         for preinit in &func_names.preinits {
             let func = instance.get_typed_func::<(), ()>(&mut store, preinit).unwrap();
             call_sync_typed_func(&func, &mut store, ()).map_err(|err| InitializationError::RuntimeError {
diff --git a/crates/smoketests/tests/smoketests/csharp_aot_module.rs b/crates/smoketests/tests/smoketests/csharp_aot_module.rs
index 56df1100861..f0d551c454a 100644
--- a/crates/smoketests/tests/smoketests/csharp_aot_module.rs
+++ b/crates/smoketests/tests/smoketests/csharp_aot_module.rs
@@ -1,30 +1,54 @@
 #![allow(clippy::disallowed_macros)]
 use spacetimedb_guard::ensure_binaries_built;
-use spacetimedb_smoketests::{have_emscripten, require_dotnet, workspace_root};
+use spacetimedb_smoketests::{require_dotnet, workspace_root};
 use std::process::Command;
 
+/// Detect the major version of the active .NET SDK.
+fn dotnet_major_version() -> Option<u8> {
+    Command::new("dotnet")
+        .arg("--version")
+        .output()
+        .ok()
+        .filter(|o| o.status.success())
+        .and_then(|o| {
+            let v = String::from_utf8_lossy(&o.stdout);
+            v.trim().split('.').next()?.parse::<u8>().ok()
+        })
+}
+
 /// Test NativeAOT-LLVM build path for C# modules.
-/// Requires emscripten to be installed.
-/// Only runs on Windows since runtime.linux-x64.Microsoft.DotNet.ILCompiler.LLVM
-/// is not available on the dotnet-experimental NuGet feed.
+///
+/// Platform support depends on the .NET SDK version:
+/// - .NET 8 AOT: Windows-only (runtime.linux-x64.Microsoft.DotNet.ILCompiler.LLVM
+///   8.0.0-* was never published to the dotnet-experimental NuGet feed).
+/// - .NET 10 AOT: Windows and Linux (both runtime packages are available).
+///
+/// NativeAOT-LLVM targets WASI and uses WASI SDK (clang), not the wasi-experimental
+/// workload or emscripten. WASI SDK is auto-downloaded by SpacetimeDB.Runtime.targets.
+/// The user must set EXPERIMENTAL_WASM_AOT=1 to enable the AOT build path.
 #[test]
 fn test_build_csharp_module_aot() {
     require_dotnet!();
 
-    // NativeAOT-LLVM is only available on Windows
-    if std::env::consts::OS != "windows" {
-        eprintln!("Skipping AOT test - NativeAOT-LLVM for .NET 8 only available on Windows");
+    let major = dotnet_major_version();
+    let target_framework = match major {
+        Some(v) if v >= 10 => "net10.0",
+        Some(8) => "net8.0",
+        _ => {
+            eprintln!("Skipping AOT test - unsupported .NET SDK version: {:?}", major);
+            return;
+        }
+    };
+
+    // .NET 8 ILCompiler.LLVM packages are only available for Windows.
+    // .NET 10+ ILCompiler.LLVM packages are available for Windows and Linux.
+    if target_framework == "net8.0" && std::env::consts::OS != "windows" {
+        eprintln!("Skipping .NET 8 AOT test - ILCompiler.LLVM 8.0.0-* only available on Windows");
         return;
     }
-
-    // Check for emscripten - fail with helpful message if not available
-    // Uses have_emscripten() which checks for both `emcc` and `emcc.bat` on Windows
-    if !have_emscripten() {
-        panic!(
-            "NativeAOT-LLVM test requires emscripten but it was not found.\n\
-             Install from: https://emscripten.org/docs/getting_started/downloads.html\n\
-             Or ensure `emcc` is in your PATH."
-        );
+    if std::env::consts::OS != "windows" && std::env::consts::OS != "linux" {
+        eprintln!("Skipping AOT test - NativeAOT-LLVM only available on Windows and Linux");
+        return;
     }
 
     let workspace = workspace_root();
@@ -57,7 +81,9 @@ fn test_build_csharp_module_aot() {
     // This ensures subsequent tests can clear NuGet locals without conflicts
     drop(nuget_packages_dir);
 
-    // Verify StdbModule.wasm was produced
-    let wasm_path = workspace.join("modules/sdk-test-cs/bin/Release/net8.0/wasi-wasm/publish/StdbModule.wasm");
+    // Verify StdbModule.wasm was produced at the correct TFM-specific output path
+    let wasm_path = workspace.join(format!(
+        "modules/sdk-test-cs/bin/Release/{target_framework}/wasi-wasm/publish/StdbModule.wasm"
+    ));
     assert!(wasm_path.exists(), "StdbModule.wasm not found at {:?}", wasm_path);
 }
diff --git a/docs/docs/00300-resources/00200-reference/00100-cli-reference/00100-cli-reference.md b/docs/docs/00300-resources/00200-reference/00100-cli-reference/00100-cli-reference.md
index fe76039a240..a874bd9fbde 100644
--- a/docs/docs/00300-resources/00200-reference/00100-cli-reference/00100-cli-reference.md
+++ b/docs/docs/00300-resources/00200-reference/00100-cli-reference/00100-cli-reference.md
@@ -111,7 +111,7 @@ Run `spacetime help publish` for more detailed information.
 * `-y`, `--yes` — Run non-interactively wherever possible. This will answer "yes" to almost all prompts, but will sometimes answer "no" to preserve non-interactivity (e.g. when prompting whether to log in with spacetimedb.com).
 * `--no-config` — Ignore spacetime.json configuration
 * `--env <ENV>` — Environment name for config file layering (e.g., dev, staging)
-* `--native-aot` — Use NativeAOT-LLVM compilation for C# modules (experimental, Windows only)
+* `--native-aot` — Use NativeAOT-LLVM compilation for C# modules targeting .NET 8 (experimental). Not needed for .NET 10, which uses NativeAOT-LLVM automatically.
 
 
 
@@ -415,7 +415,8 @@ Initializes a new spacetime project.
 * `-t`, `--template <TEMPLATE>` — Template ID or GitHub repository (owner/repo or URL)
 * `--local` — Use local deployment instead of Maincloud
 * `--non-interactive` — Run in non-interactive mode
-* `--native-aot` — Configure C# project for NativeAOT-LLVM compilation (experimental, Windows only)
+* `--native-aot` — Configure C# project for NativeAOT-LLVM compilation targeting .NET 8 (experimental). Not needed for .NET 10, which uses NativeAOT-LLVM automatically.
+* `--dotnet-version <VERSION>` — Target .NET SDK major version for C# projects (e.g., `8` or `10`). When omitted, the CLI auto-detects from the installed SDK or prompts interactively if multiple versions are available.
 
 
 
diff --git a/global.json b/global.json
index c19a2e057c7..1e7fdfa95fd 100644
--- a/global.json
+++ b/global.json
@@ -1,6 +1,6 @@
 {
   "sdk": {
-    "version": "8.0.100",
+    "version": "10.0.100",
     "rollForward": "latestMinor"
   }
 }
diff --git a/modules/Directory.Build.props b/modules/Directory.Build.props
index a03bac5df3a..e66478ad229 100644
--- a/modules/Directory.Build.props
+++ b/modules/Directory.Build.props
@@ -5,6 +5,7 @@
   <PropertyGroup>
     <TargetName>StdbModule</TargetName>
     <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework Condition="'$(EXPERIMENTAL_WASM_AOT)' == '1'">net10.0</TargetFramework>
     <RuntimeIdentifier>wasi-wasm</RuntimeIdentifier>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>

From 62f1354be67cbf30857e315f3f511eccf8546b24 Mon Sep 17 00:00:00 2001
From: rekhoff <r.ekhoff@clockworklabs.io>
Date: Wed, 29 Apr 2026 13:14:45 -0700
Subject: [PATCH 3/8] Resolved 3 CI failures

1) Created exception to `check_global_json_policy` to allow for .NET 8 templates to be generated.
2) Removed .NET 10 DLLs from SDK to prevent Unity issue.
3) Updated NativeAOT smoketest test include `packageSourceMapping` in `NuGet.Config`.
---
 crates/cli/src/subcommands/init.rs                  | 11 +++++++++++
 sdks/csharp/after.SpacetimeDB.ClientSDK.sln.targets |  1 +
 tools/ci/src/main.rs                                |  5 ++++-
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/crates/cli/src/subcommands/init.rs b/crates/cli/src/subcommands/init.rs
index bf6270e152c..2cfdf4213ac 100644
--- a/crates/cli/src/subcommands/init.rs
+++ b/crates/cli/src/subcommands/init.rs
@@ -1963,6 +1963,17 @@ fn add_native_aot_packages_to_csproj(project_path: &Path, dotnet_major: Option<u
     <add key="dotnet-experimental" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-experimental/nuget/v3/index.json" />
     <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
   </packageSources>
+  <packageSourceMapping>
+    <!-- Experimental packages for NativeAOT-LLVM compilation -->
+    <packageSource key="dotnet-experimental">
+      <package pattern="Microsoft.DotNet.ILCompiler.LLVM" />
+      <package pattern="runtime.*" />
+    </packageSource>
+    <!-- Fallback for other packages -->
+    <packageSource key="nuget.org">
+      <package pattern="*" />
+    </packageSource>
+  </packageSourceMapping>
 </configuration>
 "#;
 
diff --git a/sdks/csharp/after.SpacetimeDB.ClientSDK.sln.targets b/sdks/csharp/after.SpacetimeDB.ClientSDK.sln.targets
index a9197c5098f..bc0f150b4a5 100644
--- a/sdks/csharp/after.SpacetimeDB.ClientSDK.sln.targets
+++ b/sdks/csharp/after.SpacetimeDB.ClientSDK.sln.targets
@@ -5,6 +5,7 @@
       <ItemGroup>
          <!-- Delete doesn't support wildcards on its own, collect files into an interim ItemGroup. -->
          <_UnsupportedDLLs Include="packages/**/net8.0/**" />
+         <_UnsupportedDLLs Include="packages/**/net10.0/**" />
       </ItemGroup>
       <Delete Files="@(_UnsupportedDLLs)" />
    </Target>
diff --git a/tools/ci/src/main.rs b/tools/ci/src/main.rs
index 3c31c366324..a538679f42f 100644
--- a/tools/ci/src/main.rs
+++ b/tools/ci/src/main.rs
@@ -76,7 +76,10 @@ fn check_global_json_policy() -> Result<()> {
         }
 
         let contents = fs::read_to_string(&p)?;
-        if contents != root_contents {
+        // Templates are exempt from content matching to preserve the .NET 8 JIT path for
+        // module developers importing templates, while the main codebase uses .NET 10 AOT.
+        // TODO: Remove this exemption once .NET 10 is the default and templates should use it.
+        if contents != root_contents && !is_template_global_json {
             eprintln!("Error: {} does not match the root global.json contents", p.display());
             ok = false;
         } else if !is_template_global_json || !is_symlink {

From c3041ac4deafd6231abeb77b49a3ec011c81d93d Mon Sep 17 00:00:00 2001
From: rekhoff <r.ekhoff@clockworklabs.io>
Date: Wed, 29 Apr 2026 16:05:21 -0700
Subject: [PATCH 4/8] Update C# module smoketests for .NET 10, cli ref docs,
 and Unity Meta Skeleton

---
 .../tests/smoketests/csharp_module.rs         |  9 +++--
 .../00100-cli-reference.md                    |  6 ++--
 .../lib/net10.0.meta                          |  8 +++++
 .../SpacetimeDB.BSATN.Runtime.dll.meta        | 33 +++++++++++++++++++
 .../spacetimedb.runtime/lib/net10.0.meta      |  8 +++++
 5 files changed, 59 insertions(+), 5 deletions(-)
 create mode 100644 sdks/csharp/unity-meta-skeleton~/spacetimedb.bsatn.runtime/lib/net10.0.meta
 create mode 100644 sdks/csharp/unity-meta-skeleton~/spacetimedb.bsatn.runtime/lib/net10.0/SpacetimeDB.BSATN.Runtime.dll.meta
 create mode 100644 sdks/csharp/unity-meta-skeleton~/spacetimedb.runtime/lib/net10.0.meta

diff --git a/crates/smoketests/tests/smoketests/csharp_module.rs b/crates/smoketests/tests/smoketests/csharp_module.rs
index 6ad79e001be..b494cdc0154 100644
--- a/crates/smoketests/tests/smoketests/csharp_module.rs
+++ b/crates/smoketests/tests/smoketests/csharp_module.rs
@@ -66,8 +66,11 @@ fn test_build_csharp_module() {
     // Create nuget.config with local package sources
     // Use <clear /> to avoid inheriting sources from machine/user config
     let packed_projects = ["BSATN.Runtime", "Runtime"];
-    let mut sources =
-        String::from("    <clear />\n    <add key=\"nuget.org\" value=\"https://api.nuget.org/v3/index.json\" />\n");
+    let mut sources = String::from(
+        "    <clear />\n    <add key=\"nuget.org\" value=\"https://api.nuget.org/v3/index.json\" />\n",
+    );
+    // Add experimental NuGet feed for Microsoft.DotNet.ILCompiler.LLVM packages
+    sources.push_str("    <add key=\"dotnet-experimental\" value=\"https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-experimental/nuget/v3/index.json\" />\n");
     let mut mappings = String::new();
 
     for project in &packed_projects {
@@ -83,6 +86,8 @@ fn test_build_csharp_module() {
             package_name, package_name
         ));
     }
+    // Add mappings for experimental packages
+    mappings.push_str("    <packageSource key=\"dotnet-experimental\">\n      <package pattern=\"Microsoft.DotNet.ILCompiler.LLVM\" />\n      <package pattern=\"runtime.*\" />\n    </packageSource>\n");
     // Add fallback for other packages
     mappings.push_str("    <packageSource key=\"nuget.org\">\n      <package pattern=\"*\" />\n    </packageSource>\n");
 
diff --git a/docs/docs/00300-resources/00200-reference/00100-cli-reference/00100-cli-reference.md b/docs/docs/00300-resources/00200-reference/00100-cli-reference/00100-cli-reference.md
index a874bd9fbde..38b1ae03a97 100644
--- a/docs/docs/00300-resources/00200-reference/00100-cli-reference/00100-cli-reference.md
+++ b/docs/docs/00300-resources/00200-reference/00100-cli-reference/00100-cli-reference.md
@@ -111,7 +111,7 @@ Run `spacetime help publish` for more detailed information.
 * `-y`, `--yes` — Run non-interactively wherever possible. This will answer "yes" to almost all prompts, but will sometimes answer "no" to preserve non-interactivity (e.g. when prompting whether to log in with spacetimedb.com).
 * `--no-config` — Ignore spacetime.json configuration
 * `--env <ENV>` — Environment name for config file layering (e.g., dev, staging)
-* `--native-aot` — Use NativeAOT-LLVM compilation for C# modules targeting .NET 8 (experimental). Not needed for .NET 10, which uses NativeAOT-LLVM automatically.
+* `--native-aot` — Use NativeAOT-LLVM compilation for C# modules (experimental, Windows only)
 
 
 
@@ -415,8 +415,8 @@ Initializes a new spacetime project.
 * `-t`, `--template <TEMPLATE>` — Template ID or GitHub repository (owner/repo or URL)
 * `--local` — Use local deployment instead of Maincloud
 * `--non-interactive` — Run in non-interactive mode
-* `--native-aot` — Configure C# project for NativeAOT-LLVM compilation targeting .NET 8 (experimental). Not needed for .NET 10, which uses NativeAOT-LLVM automatically.
-* `--dotnet-version <VERSION>` — Target .NET SDK major version for C# projects (e.g., `8` or `10`). When omitted, the CLI auto-detects from the installed SDK or prompts interactively if multiple versions are available.
+* `--native-aot` — Configure C# project for NativeAOT-LLVM compilation (experimental, Windows only)
+* `--dotnet-version <VERSION>` — Target .NET SDK major version for C# projects (e.g. 8 or 10). Auto-detected when omitted.
 
 
 
diff --git a/sdks/csharp/unity-meta-skeleton~/spacetimedb.bsatn.runtime/lib/net10.0.meta b/sdks/csharp/unity-meta-skeleton~/spacetimedb.bsatn.runtime/lib/net10.0.meta
new file mode 100644
index 00000000000..4d0dbab5184
--- /dev/null
+++ b/sdks/csharp/unity-meta-skeleton~/spacetimedb.bsatn.runtime/lib/net10.0.meta
@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: 3c6f8e9a2b5d4e7f9a1b2c3d4e5f6a7b
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/sdks/csharp/unity-meta-skeleton~/spacetimedb.bsatn.runtime/lib/net10.0/SpacetimeDB.BSATN.Runtime.dll.meta b/sdks/csharp/unity-meta-skeleton~/spacetimedb.bsatn.runtime/lib/net10.0/SpacetimeDB.BSATN.Runtime.dll.meta
new file mode 100644
index 00000000000..f502b295917
--- /dev/null
+++ b/sdks/csharp/unity-meta-skeleton~/spacetimedb.bsatn.runtime/lib/net10.0/SpacetimeDB.BSATN.Runtime.dll.meta
@@ -0,0 +1,33 @@
+fileFormatVersion: 2
+guid: 7d2e8f4c9a3b5e6d8f1a2b3c4d5e6f7a
+PluginImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  iconMap: {}
+  executionOrder: {}
+  defineConstraints: []
+  isPreloaded: 0
+  isOverridable: 1
+  isExplicitlyReferenced: 0
+  validateReferences: 0
+  platformData:
+  - first:
+      Any: 
+    second:
+      enabled: 0
+      settings: {}
+  - first:
+      Editor: Editor
+    second:
+      enabled: 0
+      settings:
+        DefaultValueInitialized: true
+  - first:
+      Windows Store Apps: WindowsStoreApps
+    second:
+      enabled: 0
+      settings:
+        CPU: AnyCPU
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/sdks/csharp/unity-meta-skeleton~/spacetimedb.runtime/lib/net10.0.meta b/sdks/csharp/unity-meta-skeleton~/spacetimedb.runtime/lib/net10.0.meta
new file mode 100644
index 00000000000..7246b376f90
--- /dev/null
+++ b/sdks/csharp/unity-meta-skeleton~/spacetimedb.runtime/lib/net10.0.meta
@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: 9a8b7c6d5e4f3a2b1c0d9e8f7a6b5c4d
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

From 98216f9ff61b4c6d76daabed2ef75813ee011640 Mon Sep 17 00:00:00 2001
From: rekhoff <r.ekhoff@clockworklabs.io>
Date: Wed, 29 Apr 2026 16:15:34 -0700
Subject: [PATCH 5/8] Update lint

---
 crates/smoketests/tests/smoketests/csharp_module.rs | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/crates/smoketests/tests/smoketests/csharp_module.rs b/crates/smoketests/tests/smoketests/csharp_module.rs
index b494cdc0154..78acfa7b211 100644
--- a/crates/smoketests/tests/smoketests/csharp_module.rs
+++ b/crates/smoketests/tests/smoketests/csharp_module.rs
@@ -66,9 +66,8 @@ fn test_build_csharp_module() {
     // Create nuget.config with local package sources
     // Use <clear /> to avoid inheriting sources from machine/user config
     let packed_projects = ["BSATN.Runtime", "Runtime"];
-    let mut sources = String::from(
-        "    <clear />\n    <add key=\"nuget.org\" value=\"https://api.nuget.org/v3/index.json\" />\n",
-    );
+    let mut sources =
+        String::from("    <clear />\n    <add key=\"nuget.org\" value=\"https://api.nuget.org/v3/index.json\" />\n");
     // Add experimental NuGet feed for Microsoft.DotNet.ILCompiler.LLVM packages
     sources.push_str("    <add key=\"dotnet-experimental\" value=\"https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-experimental/nuget/v3/index.json\" />\n");
     let mut mappings = String::new();

From 1fe6d8b48732c85bbf936c93b2c6aa041cc9b7b5 Mon Sep 17 00:00:00 2001
From: rekhoff <r.ekhoff@clockworklabs.io>
Date: Wed, 29 Apr 2026 18:08:43 -0700
Subject: [PATCH 6/8] Adding additional `dotnet-experimental` package sources

---
 crates/smoketests/src/csharp.rs                 |  5 +++++
 crates/smoketests/tests/smoketests/templates.rs | 10 ++++++++++
 2 files changed, 15 insertions(+)

diff --git a/crates/smoketests/src/csharp.rs b/crates/smoketests/src/csharp.rs
index 5b832f4781f..e4b33adba70 100644
--- a/crates/smoketests/src/csharp.rs
+++ b/crates/smoketests/src/csharp.rs
@@ -172,12 +172,17 @@ pub(crate) fn prepare_csharp_module(module_path: &Path) -> Result<()> {
   <packageSources>
     <clear />
     <add key="spacetimedb-local" value="{}" />
+    <add key="dotnet-experimental" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-experimental/nuget/v3/index.json" />
     <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
   </packageSources>
   <packageSourceMapping>
     <packageSource key="spacetimedb-local">
       <package pattern="SpacetimeDB.*" />
     </packageSource>
+    <packageSource key="dotnet-experimental">
+      <package pattern="Microsoft.DotNet.ILCompiler.LLVM" />
+      <package pattern="runtime.*" />
+    </packageSource>
     <packageSource key="nuget.org">
       <package pattern="*" />
     </packageSource>
diff --git a/crates/smoketests/tests/smoketests/templates.rs b/crates/smoketests/tests/smoketests/templates.rs
index 8de55871f58..da7716d6f71 100644
--- a/crates/smoketests/tests/smoketests/templates.rs
+++ b/crates/smoketests/tests/smoketests/templates.rs
@@ -574,7 +574,17 @@ fn setup_csharp_nuget(project_path: &Path) -> Result<PathBuf> {
   <packageSources>
     <clear />
     <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
+    <add key="dotnet-experimental" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-experimental/nuget/v3/index.json" />
   </packageSources>
+  <packageSourceMapping>
+    <packageSource key="dotnet-experimental">
+      <package pattern="Microsoft.DotNet.ILCompiler.LLVM" />
+      <package pattern="runtime.*" />
+    </packageSource>
+    <packageSource key="nuget.org">
+      <package pattern="*" />
+    </packageSource>
+  </packageSourceMapping>
 </configuration>
 "#,
         )

From 8008c6e60d1086797837082d2c9a7e499cfdbb2b Mon Sep 17 00:00:00 2001
From: rekhoff <r.ekhoff@clockworklabs.io>
Date: Wed, 29 Apr 2026 19:25:13 -0700
Subject: [PATCH 7/8] Group package by source and install WASI SDK on Linux

---
 .github/workflows/ci.yml                         | 10 ++++++++++
 crates/smoketests/tests/smoketests/quickstart.rs | 14 ++++++++++----
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 69bfe7f0e76..291d1cedbbd 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -94,6 +94,16 @@ jobs:
           ./emsdk install 4.0.21
           ./emsdk activate 4.0.21
 
+      # Install WASI SDK for .NET 10 NativeAOT-LLVM compilation.
+      - name: Install WASI SDK (Linux)
+        if: runner.os == 'Linux'
+        shell: bash
+        run: |
+          wget https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-29/wasi-sdk-29.0-x86_64-linux.tar.gz
+          tar -xzf wasi-sdk-29.0-x86_64-linux.tar.gz
+          sudo mv wasi-sdk-29.0 /opt/wasi-sdk
+          echo "WASI_SDK_PATH=/opt/wasi-sdk" >> "$GITHUB_ENV"
+
       - name: Install emscripten (Windows)
         if: runner.os == 'Windows'
         shell: pwsh
diff --git a/crates/smoketests/tests/smoketests/quickstart.rs b/crates/smoketests/tests/smoketests/quickstart.rs
index 39de1f501a8..1566d9b5645 100644
--- a/crates/smoketests/tests/smoketests/quickstart.rs
+++ b/crates/smoketests/tests/smoketests/quickstart.rs
@@ -111,11 +111,17 @@ fn create_nuget_config(sources: &[(String, PathBuf)], mappings: &[(String, Strin
         source_lines.push_str(&format!("    <add key=\"{}\" value=\"{}\" />\n", key, path.display()));
     }
 
+    let mut patterns_by_source: std::collections::HashMap<String, Vec<String>> = std::collections::HashMap::new();
     for (key, pattern) in mappings {
-        mapping_lines.push_str(&format!(
-            "    <packageSource key=\"{}\">\n      <package pattern=\"{}\" />\n    </packageSource>\n",
-            key, pattern
-        ));
+        patterns_by_source.entry(key.clone()).or_default().push(pattern.clone());
+    }
+
+    for (key, patterns) in patterns_by_source {
+        mapping_lines.push_str(&format!("    <packageSource key=\"{}\">\n", key));
+        for pattern in patterns {
+            mapping_lines.push_str(&format!("      <package pattern=\"{}\" />\n", pattern));
+        }
+        mapping_lines.push_str("    </packageSource>\n");
     }
 
     format!(

From e3e1d7877b5c0ac04ac507fdfd84c83b5df8754b Mon Sep 17 00:00:00 2001
From: rekhoff <r.ekhoff@clockworklabs.io>
Date: Wed, 29 Apr 2026 19:59:49 -0700
Subject: [PATCH 8/8] Target Linux WASI SDK

---
 .github/workflows/ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 291d1cedbbd..a6b0fc51fe7 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -101,7 +101,7 @@ jobs:
         run: |
           wget https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-29/wasi-sdk-29.0-x86_64-linux.tar.gz
           tar -xzf wasi-sdk-29.0-x86_64-linux.tar.gz
-          sudo mv wasi-sdk-29.0 /opt/wasi-sdk
+          sudo mv wasi-sdk-29.0-x86_64-linux /opt/wasi-sdk
           echo "WASI_SDK_PATH=/opt/wasi-sdk" >> "$GITHUB_ENV"
 
       - name: Install emscripten (Windows)