diff --git a/.github/workflows/python-app.yml b/.github/workflows/python-app.yml
index 67014ba..1d529a2 100644
--- a/.github/workflows/python-app.yml
+++ b/.github/workflows/python-app.yml
@@ -12,9 +12,6 @@ on:
   pull_request:
     branches: [ master ]
 
-env:
-  PYTHON_VERSION: 3.13.3
-
 jobs:
   lint:
     runs-on: ubuntu-latest
@@ -25,10 +22,10 @@ jobs:
       - name: Lint commit messages
         uses: wagoid/commitlint-github-action@v6.2.1
 
-      - name: Set up Python ${{ env.PYTHON_VERSION }}
-        uses: actions/setup-python@v6.1.0
+      - name: Set up Python
+        uses: actions/setup-python@v6.0.0
         with:
-          python-version: ${{ env.PYTHON_VERSION }}
+          python-version-file: '.python-version'
           cache: 'pip'
 
       - name: Install lint dependencies
@@ -51,10 +48,10 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v6.0.0
 
-      - name: Set up Python ${{ env.PYTHON_VERSION }}
+      - name: Set up Python
         uses: actions/setup-python@v6.1.0
         with:
-          python-version: ${{ env.PYTHON_VERSION }}
+          python-version-file: '.python-version'
           cache: 'pip'
 
       - name: Install test dependencies
diff --git a/.gitignore b/.gitignore
index 6f316ab..7d392e5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -86,7 +86,7 @@ ipython_config.py
 # pyenv
 #   For a library or package, you might want to ignore these files since the code is
 #   intended to run in multiple environments; otherwise, check them in:
-# .python-version
+# Track .python-version for consistent Python version across environments
 
 # pipenv
 #   According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control.
@@ -158,4 +158,4 @@ cython_debug/
 #  be found at https://github.com/github/gitignore/blob/main/Global/JetBrains.gitignore
 #  and can be added to the global gitignore or merged into this file.  For a more nuclear
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
-#.idea/
\ No newline at end of file
+#.idea/
diff --git a/.python-version b/.python-version
new file mode 100644
index 0000000..2c20ac9
--- /dev/null
+++ b/.python-version
@@ -0,0 +1 @@
+3.13.3
diff --git a/Dockerfile b/Dockerfile
index d6e6c52..04d747a 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,6 +2,7 @@
 # Stage 1: Builder
 # This stage builds the application and its dependencies.
 # ------------------------------------------------------------------------------
+# Python version should match .python-version file (currently 3.13.3)
 FROM python:3.13.3-slim-bookworm AS builder
 
 WORKDIR /app
@@ -19,6 +20,7 @@ RUN pip wheel --no-cache-dir --wheel-dir=/app/wheelhouse -r requirements.txt
 # Stage 2: Runtime
 # This stage creates the final, minimal image to run the application.
 # ------------------------------------------------------------------------------
+# Python version should match .python-version file (currently 3.13.3)
 FROM python:3.13.3-slim-bookworm AS runtime
 
 WORKDIR /app
diff --git a/README.md b/README.md
index 99ec439..2f8f1a0 100644
--- a/README.md
+++ b/README.md
@@ -19,6 +19,12 @@ Proof of Concept for a RESTful API made with [Python 3](https://www.python.org/)
 
 _Figure: Simplified, conceptual project structure and main application flow. Not all dependencies are shown._
 
+## Python Version Management
+
+This project uses `.python-version` to specify the required Python version. If you use [pyenv](https://github.com/pyenv/pyenv), [asdf](https://asdf-vm.com/), or [mise](https://mise.jdx.dev/), the correct Python version will be automatically activated when you enter the project directory.
+
+Alternatively, ensure you have Python 3.13.3 (or the version specified in `.python-version`) installed.
+
 ## Install
 
 ```console
diff --git a/runtime.txt b/runtime.txt
deleted file mode 100644
index b50f9b0..0000000
--- a/runtime.txt
+++ /dev/null
@@ -1 +0,0 @@
-python-3.13.3