diff --git a/.devcontainer/Dockerfile.dev b/.devcontainer/Dockerfile.dev
new file mode 100644
index 0000000..5bce3e0
--- /dev/null
+++ b/.devcontainer/Dockerfile.dev
@@ -0,0 +1,27 @@
+ARG UV_VERSION=0.8.13
+
+FROM ghcr.io/astral-sh/uv:${UV_VERSION} AS uv
+
+FROM mcr.microsoft.com/devcontainers/base:bookworm
+
+COPY --from=uv /uv /uvx /bin/
+
+# Python environment variables for development
+ENV PYTHONUNBUFFERED=1 \
+    PYTHONDONTWRITEBYTECODE=1 \
+    PYTHONIOENCODING=utf-8 \
+    PIP_NO_CACHE_DIR=1 \
+    PIP_DISABLE_PIP_VERSION_CHECK=1 \
+    UV_NO_CACHE=1 \
+    UV_PROJECT_ENVIRONMENT=/app/.venv \
+    LANG=C.UTF-8 \
+    LC_ALL=C.UTF-8
+
+USER vscode
+
+SHELL ["/bin/bash", "-o", "pipefail", "-c"]
+
+WORKDIR /app
+
+HEALTHCHECK --interval=60s --timeout=5s --start-period=60s --retries=3 \
+    CMD test -d /app && whoami || exit 1
diff --git a/.devcontainer/README.md b/.devcontainer/README.md
new file mode 100644
index 0000000..0fb4953
--- /dev/null
+++ b/.devcontainer/README.md
@@ -0,0 +1,120 @@
+# Development Container
+
+This project uses a [Development Container](https://containers.dev/) to provide a consistent development environment.
+
+## Getting Started
+
+1. Install [Docker Desktop](https://www.docker.com/products/docker-desktop)
+2. Install [VS Code](https://code.visualstudio.com/) and the [Dev Containers extension](https://marketplace.visualstudio.com/items?itemName=ms-vscode-remote.remote-containers)
+3. Open this folder in VS Code
+4. When prompted, click "Reopen in Container" (or run command: `Dev Containers: Reopen in Container`)
+
+## Local Customization
+
+To customize your local development environment without modifying the committed configuration, create a `.devcontainer/devcontainer.local.json` file (this file is gitignored).
+
+### Example: Add Additional VS Code Extensions
+
+```json
+{
+  "customizations": {
+    "vscode": {
+      "extensions": [
+        "esbenp.prettier-vscode",
+        "usernamehw.errorlens"
+      ]
+    }
+  }
+}
+```
+
+### Example: Mount Additional Volumes
+
+```json
+{
+  "mounts": [
+    "source=${localEnv:HOME}/.gitconfig,target=/home/vscode/.gitconfig,type=bind,consistency=cached"
+  ]
+}
+```
+
+### Example: Override or Add Environment Variables
+
+The container sets several Python-related environment variables by default (see `Dockerfile.dev`). You can override them or add new ones using `remoteEnv`:
+
+```json
+{
+  "remoteEnv": {
+    "PYTHONUNBUFFERED": "0",
+    "DEBUG": "1",
+    "LOG_LEVEL": "DEBUG"
+  }
+}
+```
+
+See `devcontainer.local.json.example` for a complete list of default environment variables that can be overridden.
+
+Alternatively, create a `.devcontainer/.env` file (also gitignored):
+```bash
+DEBUG=1
+LOG_LEVEL=DEBUG
+```
+
+And reference it in `devcontainer.local.json`:
+```json
+{
+  "runArgs": ["--env-file", ".devcontainer/.env"]
+}
+```
+
+### Example: Forward Additional Ports
+
+```json
+{
+  "forwardPorts": [8080, 3000]
+}
+```
+
+## How It Works
+
+The Dev Container will:
+- Build from `Dockerfile.dev`
+- Mount your workspace to `/app`
+- Install Git and GitHub CLI features
+- Run `uv sync --all-groups` to create a virtual environment at `/app/.venv`
+- Configure VS Code to use the virtual environment's Python interpreter
+- Set up bash as the default terminal
+
+### Default Environment Variables
+
+The following Python-related environment variables are set in the container:
+
+- **`PYTHONUNBUFFERED=1`** - Ensures real-time output in logs
+- **`PYTHONDONTWRITEBYTECODE=1`** - Prevents `.pyc` file creation
+- **`PYTHONIOENCODING=utf-8`** - Ensures UTF-8 encoding for I/O
+- **`PIP_NO_CACHE_DIR=1`** - Disables pip caching to reduce container size
+- **`PIP_DISABLE_PIP_VERSION_CHECK=1`** - Suppresses pip update warnings
+- **`UV_NO_CACHE=1`** - Disables uv caching
+- **`UV_PROJECT_ENVIRONMENT=/app/.venv`** - Sets the virtual environment location for uv
+- **`LANG=C.UTF-8`** - Sets locale for proper Unicode handling
+- **`LC_ALL=C.UTF-8`** - Sets all locale categories to UTF-8
+
+These can be overridden in `devcontainer.local.json` using the `remoteEnv` property.
+
+### Virtual Environment
+
+The project uses `uv` to manage dependencies. When the container is created:
+1. `uv sync --all-groups` is automatically run to create a virtual environment at `/app/.venv`
+2. VS Code is configured to use `/app/.venv/bin/python` as the Python interpreter
+3. All dependencies from `pyproject.toml` (including dev groups) are installed
+
+To manually update dependencies, run:
+```bash
+uv sync --all-groups
+```
+
+## Rebuilding the Container
+
+If you modify the Dockerfile or devcontainer configuration:
+1. Run command: `Dev Containers: Rebuild Container`
+2. Or run: `Dev Containers: Rebuild Container Without Cache` for a clean build
diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
new file mode 100644
index 0000000..a686774
--- /dev/null
+++ b/.devcontainer/devcontainer.json
@@ -0,0 +1,30 @@
+{
+  // To customize this for your local environment without committing changes,
+  // create a .devcontainer/devcontainer.local.json file (it's gitignored).
+  // See .devcontainer/README.md for examples.
+  "name": "toon-python (devcontainer)",
+  "build": {
+    "dockerfile": "Dockerfile.dev",
+    "context": ".."
+  },
+  "workspaceFolder": "/app",
+  "mounts": [
+    "source=${localWorkspaceFolder},target=/app,type=bind,consistency=cached"
+  ],
+  "features": {
+    "ghcr.io/devcontainers/features/git:1": {},
+    "ghcr.io/devcontainers/features/github-cli:1": {}
+  },
+  "remoteEnv": {
+    // Python environment variables (can be overridden in devcontainer.local.json)
+    // These supplement the ENV vars set in Dockerfile.dev
+  },
+  "postCreateCommand": "uv sync --all-groups",
+  "customizations": {
+    "vscode": {
+      "settings": {
+        "python.defaultInterpreterPath": "/app/.venv/bin/python"
+      }
+    }
+  }
+}
diff --git a/.devcontainer/devcontainer.local.json.example b/.devcontainer/devcontainer.local.json.example
new file mode 100644
index 0000000..65e0d3f
--- /dev/null
+++ b/.devcontainer/devcontainer.local.json.example
@@ -0,0 +1,32 @@
+{
+  // Example local devcontainer configuration
+  // Copy this to devcontainer.local.json and customize as needed
+  // This file is gitignored and won't be committed
+  
+  "remoteEnv": {
+    // Override Python environment variables
+    // Uncomment and modify any of these to override defaults from Dockerfile.dev:
+    
+    // "PYTHONUNBUFFERED": "0",
+    // "PYTHONDONTWRITEBYTECODE": "0",
+    // "PYTHONIOENCODING": "utf-8",
+    // "PIP_NO_CACHE_DIR": "0",
+    // "PIP_DISABLE_PIP_VERSION_CHECK": "0",
+    // "UV_NO_CACHE": "0",
+    // "UV_PROJECT_ENVIRONMENT": "/custom/path/.venv",
+    // "LANG": "en_US.UTF-8",
+    // "LC_ALL": "en_US.UTF-8",
+    
+    // Add custom environment variables for local development:
+    // "DEBUG": "1",
+    // "LOG_LEVEL": "DEBUG"
+  },
+  
+  // You can also override other devcontainer settings:
+  // "features": {},
+  // "customizations": {
+  //   "vscode": {
+  //     "extensions": []
+  //   }
+  // }
+}
diff --git a/.gitignore b/.gitignore
index e14d4f7..0575f02 100644
--- a/.gitignore
+++ b/.gitignore
@@ -64,6 +64,7 @@ venv/
 ENV/
 env.bak/
 venv.bak/
+.python-version
 
 # IDEs
 .vscode/
@@ -74,6 +75,10 @@ venv.bak/
 .claude/
 CLAUDE.md
 
+# DevContainer local overrides
+.devcontainer/devcontainer.local.json
+.devcontainer/.env
+
 # macOS
 .DS_Store
 .AppleDouble
diff --git a/.python-version b/.python-version
deleted file mode 100644
index 6324d40..0000000
--- a/.python-version
+++ /dev/null
@@ -1 +0,0 @@
-3.14