flowable · filiphr · Feb 13, 2026
diff --git a/modules/flowable-http-common/src/main/java/org/flowable/http/common/api/MultiValuePart.java b/modules/flowable-http-common/src/main/java/org/flowable/http/common/api/MultiValuePart.java
@@ -56,6 +56,10 @@ public static MultiValuePart fromText(String name, String value) {
         return new MultiValuePart(name, value, null);
     }
 
+    public static MultiValuePart fromText(String name, String value, String mimeType) {
+        return new MultiValuePart(name, value, null, mimeType);
+    }
+
     public static MultiValuePart fromFile(String name, byte[] value, String filename) {
         return new MultiValuePart(name, value, filename);
     }

diff --git a/...es/flowable-http-common/src/main/java/org/flowable/http/common/impl/HttpClientConfig.java b/...es/flowable-http-common/src/main/java/org/flowable/http/common/impl/HttpClientConfig.java
@@ -92,6 +92,22 @@ public class HttpClientConfig {
 
     protected boolean useSystemProperties = false;
 
+    /**
+     * The multipart mode to use when building multipart/form-data requests with the Apache HTTP client implementations.
+     * <p>
+     * Supported values:
+     * <ul>
+     *     <li>{@code "STRICT"} - RFC 2046 compliant. Always writes Content-Type headers for all parts,
+     *     including text parts. This is the default and is needed for text parts with a custom mime type to work correctly.</li>
+     *     <li>{@code "BROWSER_COMPATIBLE"} - Mimics browser behavior. Only writes Content-Type headers for parts with a filename.
+     *     This was the default before 8.0. Note that text parts with a custom mime type will not have their Content-Type sent
+     *     in this mode.</li>
+     * </ul>
+     * <p>
+     * This setting has no effect on the Spring WebClient implementation.
+     */
+    protected String multipartMode = "STRICT";
+
     protected FlowableHttpClient httpClient;
     protected Runnable closeRunnable;
 
@@ -148,6 +164,14 @@ public boolean isUseSystemProperties() {
         return useSystemProperties;
     }
 
+    public String getMultipartMode() {
+        return multipartMode;
+    }
+
+    public void setMultipartMode(String multipartMode) {
+        this.multipartMode = multipartMode;
+    }
+
     public void merge(HttpClientConfig other) {
         if (this.connectTimeout != other.getConnectTimeout()) {
             setConnectTimeout(other.getConnectTimeout());
@@ -173,6 +197,10 @@ public void merge(HttpClientConfig other) {
             setUseSystemProperties(other.isUseSystemProperties());
         }
 
+        if (!Objects.equals(this.multipartMode, other.getMultipartMode())) {
+            setMultipartMode(other.getMultipartMode());
+        }
+
         if (!Objects.equals(this.httpClient, other.getHttpClient())) {
             setHttpClient(other.getHttpClient());
         }

diff --git a/...ain/java/org/flowable/http/common/impl/apache/ApacheHttpComponentsFlowableHttpClient.java b/...ain/java/org/flowable/http/common/impl/apache/ApacheHttpComponentsFlowableHttpClient.java
@@ -102,6 +102,7 @@ public class ApacheHttpComponentsFlowableHttpClient implements FlowableHttpClien
     protected final Logger logger = LoggerFactory.getLogger(getClass());
 
     protected HttpClientBuilder clientBuilder;
+    protected HttpMultipartMode multipartMode;
     protected int socketTimeout;
     protected int connectTimeout;
     protected int connectionRequestTimeout;
@@ -149,6 +150,7 @@ public boolean verify(String s, SSLSession sslSession) {
 
         this.clientBuilder = httpClientBuilder;
 
+        this.multipartMode = resolveMultipartMode(config.getMultipartMode());
         this.socketTimeout = config.getSocketTimeout();
         this.connectTimeout = config.getConnectTimeout();
         this.connectionRequestTimeout = config.getConnectionRequestTimeout();
@@ -157,11 +159,24 @@ public boolean verify(String s, SSLSession sslSession) {
     public ApacheHttpComponentsFlowableHttpClient(HttpClientBuilder clientBuilder, int socketTimeout, int connectTimeout,
             int connectionRequestTimeout) {
         this.clientBuilder = clientBuilder;
+        this.multipartMode = HttpMultipartMode.STRICT;
         this.socketTimeout = socketTimeout;
         this.connectTimeout = connectTimeout;
         this.connectionRequestTimeout = connectionRequestTimeout;
     }
 
+    protected static HttpMultipartMode resolveMultipartMode(String mode) {
+        if (mode == null) {
+            return HttpMultipartMode.STRICT;
+        }
+        return switch (mode.toUpperCase()) {
+            case "BROWSER_COMPATIBLE" -> HttpMultipartMode.BROWSER_COMPATIBLE;
+            case "STRICT" -> HttpMultipartMode.STRICT;
+            default -> throw new FlowableIllegalArgumentException("Unsupported multipart mode: " + mode
+                    + ". Supported values are: STRICT, BROWSER_COMPATIBLE");
+        };
+    }
+
     @Override
     public ExecutableHttpRequest prepareRequest(HttpRequest requestInfo) {
         try {
@@ -235,7 +250,7 @@ protected void setRequestEntity(HttpRequest requestInfo, HttpEntityEnclosingRequ
         } else if (requestInfo.getMultiValueParts() != null) {
             if (MULTIPART_ENTITY_BUILDER_PRESENT) {
                 MultipartEntityBuilder entityBuilder = MultipartEntityBuilder.create();
-                entityBuilder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
+                entityBuilder.setMode(multipartMode);
                 for (MultiValuePart part : requestInfo.getMultiValueParts()) {
                     String name = part.getName();
                     Object value = part.getBody();
@@ -246,7 +261,11 @@ protected void setRequestEntity(HttpRequest requestInfo, HttpEntityEnclosingRequ
                             entityBuilder.addBinaryBody(name, (byte[]) value, ContentType.DEFAULT_BINARY, part.getFilename());
                         }
                     } else if (value instanceof String) {
-                        entityBuilder.addTextBody(name, (String) value);
+                        if (StringUtils.isNotBlank(part.getMimeType())) {
+                            entityBuilder.addTextBody(name, (String) value, ContentType.create(part.getMimeType()));
+                        } else {
+                            entityBuilder.addTextBody(name, (String) value);
+                        }
                     } else if (value != null) {
                         throw new FlowableIllegalArgumentException("Value of type " + value.getClass() + " is not supported as multi part content");
                     }

diff --git a/...org/flowable/http/common/impl/apache/client5/ApacheHttpComponents5FlowableHttpClient.java b/...org/flowable/http/common/impl/apache/client5/ApacheHttpComponents5FlowableHttpClient.java
@@ -86,6 +86,7 @@ public class ApacheHttpComponents5FlowableHttpClient implements FlowableAsyncHtt
 
     protected HttpAsyncClient client;
     protected boolean closeClient;
+    protected HttpMultipartMode multipartMode;
     protected int socketTimeout;
     protected int connectTimeout;
     protected int connectionRequestTimeout;
@@ -133,6 +134,7 @@ public ApacheHttpComponents5FlowableHttpClient(HttpClientConfig config, Consumer
         this.client = client;
         this.closeClient = true;
 
+        this.multipartMode = resolveMultipartMode(config.getMultipartMode());
         this.socketTimeout = config.getSocketTimeout();
         this.connectTimeout = config.getConnectTimeout();
         this.connectionRequestTimeout = config.getConnectionRequestTimeout();
@@ -141,11 +143,25 @@ public ApacheHttpComponents5FlowableHttpClient(HttpClientConfig config, Consumer
     public ApacheHttpComponents5FlowableHttpClient(HttpAsyncClient client, int socketTimeout, int connectTimeout,
             int connectionRequestTimeout) {
         this.client = client;
+        this.multipartMode = HttpMultipartMode.STRICT;
         this.socketTimeout = socketTimeout;
         this.connectTimeout = connectTimeout;
         this.connectionRequestTimeout = connectionRequestTimeout;
     }
 
+    protected static HttpMultipartMode resolveMultipartMode(String mode) {
+        if (mode == null) {
+            return HttpMultipartMode.STRICT;
+        }
+        return switch (mode.toUpperCase()) {
+            case "BROWSER_COMPATIBLE", "LEGACY" -> HttpMultipartMode.LEGACY;
+            case "STRICT" -> HttpMultipartMode.STRICT;
+            case "EXTENDED" -> HttpMultipartMode.EXTENDED;
+            default -> throw new FlowableIllegalArgumentException("Unsupported multipart mode: " + mode
+                    + ". Supported values are: STRICT, BROWSER_COMPATIBLE, LEGACY, EXTENDED");
+        };
+    }
+
     public void close() {
         if (closeClient && client instanceof ModalCloseable) {
             ((ModalCloseable) client).close(CloseMode.GRACEFUL);
@@ -220,7 +236,7 @@ protected void setRequestEntity(HttpRequest requestInfo, AsyncRequestBuilder req
             }
         } else if (requestInfo.getMultiValueParts() != null) {
             MultipartEntityBuilder entityBuilder = MultipartEntityBuilder.create();
-            entityBuilder.setMode(HttpMultipartMode.LEGACY);
+            entityBuilder.setMode(multipartMode);
             for (MultiValuePart part : requestInfo.getMultiValueParts()) {
                 String name = part.getName();
                 Object value = part.getBody();
@@ -231,7 +247,11 @@ protected void setRequestEntity(HttpRequest requestInfo, AsyncRequestBuilder req
                         entityBuilder.addBinaryBody(name, (byte[]) value, ContentType.DEFAULT_BINARY, part.getFilename());
                     }
                 } else if (value instanceof String) {
-                    entityBuilder.addTextBody(name, (String) value);
+                    if (StringUtils.isNotBlank(part.getMimeType())) {
+                        entityBuilder.addTextBody(name, (String) value, ContentType.create(part.getMimeType()));
+                    } else {
+                        entityBuilder.addTextBody(name, (String) value);
+                    }
                 } else if (value != null) {
                     throw new FlowableIllegalArgumentException("Value of type " + value.getClass() + " is not supported as multi part content");
                 }

diff --git a/...tp/src/test/java/org/flowable/http/BrowserCompatibleApacheHttpClientArgumentProvider.java b/...tp/src/test/java/org/flowable/http/BrowserCompatibleApacheHttpClientArgumentProvider.java
@@ -0,0 +1,52 @@
+/* Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.flowable.http;
+
+import java.time.Duration;
+import java.util.stream.Stream;
+
+import org.flowable.http.common.impl.HttpClientConfig;
+import org.flowable.http.common.impl.apache.ApacheHttpComponentsFlowableHttpClient;
+import org.flowable.http.common.impl.apache.client5.ApacheHttpComponents5FlowableHttpClient;
+import org.junit.jupiter.api.extension.ExtensionContext;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.ArgumentsProvider;
+import org.junit.jupiter.params.support.ParameterDeclarations;
+
+/**
+ * @author Filip Hrisafov
+ */
+public class BrowserCompatibleApacheHttpClientArgumentProvider implements ArgumentsProvider {
+
+    @Override
+    public Stream<? extends Arguments> provideArguments(ParameterDeclarations parameters, ExtensionContext context) {
+        HttpClientConfig config = createClientConfig();
+        return Stream.of(
+                Arguments.of(new ApacheHttpComponentsFlowableHttpClient(config)),
+                Arguments.of(new ApacheHttpComponents5FlowableHttpClient(config))
+        );
+    }
+
+    protected HttpClientConfig createClientConfig() {
+        HttpClientConfig config = new HttpClientConfig();
+        config.setConnectTimeout(Duration.ofSeconds(5));
+        config.setSocketTimeout(Duration.ofSeconds(5));
+        config.setConnectionRequestTimeout(Duration.ofSeconds(5));
+        config.setRequestRetryLimit(5);
+        config.setDisableCertVerify(true);
+        config.setMultipartMode("BROWSER_COMPATIBLE");
+
+        return config;
+    }
+
+}