datamodel-code-generator

🚀 Generate Python data models from schema definitions in seconds.

📚 Documentation · 🧪 Playground · 💼 Lead maintainer available for work

[!NOTE] Playground privacy: Generation runs locally in your browser with Pyodide. Your schema and options are not sent to a backend. Shared repro URLs encode them in the URL fragment (#state=...), which browsers do not send to the server; the full URL can still be stored in your browser history or wherever you share it.

✨ What it does

Pick any one of the supported inputs and pick the Python model style you want as output. --input-model path/to/file.py:ClassName can even retarget an existing Pydantic, dataclass, or TypedDict class defined in another Python file to a different output type.

• 📄 Converts OpenAPI 3, AsyncAPI, JSON Schema, Apache Avro, XML Schema, Protocol Buffers/gRPC, GraphQL, MCP tool schemas, and raw data (JSON/YAML/CSV) into Python models
• 🐍 Generates from existing Python types (Pydantic, dataclass, TypedDict) via --input-model
• 🎯 Generates Pydantic v2, Pydantic v2 dataclass, dataclasses, TypedDict, or msgspec output
• 🌐 Generates a typed HTTPX2 client (--generate-client httpx2, from OpenAPI and AsyncAPI) or a FastAPI server (--generate-server fastapi, from OpenAPI) together with the models (experimental)
• 🔗 Handles complex schemas: $ref, allOf, oneOf, anyOf, enums, and nested types
• ✅ Produces type-safe, validated code ready for your IDE and type checker

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📦 Installation

Recommended for standalone CLI use:

uv tool install datamodel-code-generator

Conda users can install from conda-forge:

conda install -c conda-forge datamodel-code-generator

For projects that should pin the generator version, add it as a development dependency instead:

uv add --dev datamodel-code-generator

[!NOTE] Community-maintained distribution packages are also available from Debian, Ubuntu, nixpkgs, and openSUSE Tumbleweed. Availability and versions vary by distribution.

pip:

pip install datamodel-code-generator

uv (run without adding to project):

uv run --with datamodel-code-generator datamodel-codegen --help

With stable HTTP support (for resolving remote $ref):

pip install 'datamodel-code-generator[http]'

The http extra is supported and is not deprecated. To require the experimental HTTPX2 backend instead, install datamodel-code-generator[httpx2] and pass --http-backend httpx2. The experimental extra is not included in datamodel-code-generator[all]. See HTTP backend selection for automatic and explicit selection behavior.

With GraphQL support:

pip install 'datamodel-code-generator[graphql]'

With Protocol Buffers support:

pip install 'datamodel-code-generator[protobuf]'

Docker:

docker pull koxudaxi/datamodel-code-generator

Published Docker images run as a non-root appuser. When writing generated files to a bind-mounted directory, make sure the directory is writable by the container user or pass an explicit Docker user, for example --user "$(id -u):$(id -g)".

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🏃 Quick Start

Command

datamodel-codegen \
  --input schema.json \
  --input-file-type jsonschema \
  --output-model-type pydantic_v2.BaseModel \
  --preset standard-py312-20261112 \
  --output model.py

This quick start uses standard-py312-20261112 as the modern Python 3.12 baseline. Preset names include the target Python version: py312 means Python 3.12.

See CLI Reference for all options. See Presets, --preset, --input-file-type, and --output-model-type for this command.

For more schema-aware output that preserves schema-authored names, reuses models, and embeds generated documentation, use practical-py312-20261112.

This is the beginning of the README. Read the rest at the original. Read the full README ↗