MetaEngine OpenAPI Python httpx

Generate idiomatic Python clients and models from OpenAPI/Swagger specifications.

Pydantic v2 models and an async httpx client — typed, with optional docstrings, validation, and camelCase field aliases.

No .NET required. Unlike most MetaEngine wrappers, each wheel bundles a self-contained, platform-native binary — pip install and run. There is nothing else to install.

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Quick Links

• PyPI Package: metaengine-openapi-httpx
• NuGet Package: MetaEngine.Python.OpenApi.Httpx
• Website: metaengine.eu

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Features

• ✅ Self-contained - Bundled native binary per platform; no .NET runtime to install
• ✅ Pydantic v2 models - BaseModel with ConfigDict, typed fields, required vs optional
• ✅ Async httpx client - One service class per OpenAPI tag, model_validate on responses
• ✅ camelCase aliases - snake_case Python properties mapped to camelCase wire names via Field(alias=...)
• ✅ Enums - Standalone Python enum types, properly serialized
• ✅ Docstrings - Optional doc-comment generation from OpenAPI descriptions and examples
• ✅ Tag Filtering - Generate only the operations you need
• ✅ Options Object - Collapse long parameter lists into an options object past a threshold

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Installation

pip install metaengine-openapi-httpx

Pre-built wheels are published for Linux (x86_64, aarch64), macOS (Apple Silicon + Intel), and Windows (x64).

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Requirements

• Python 3.8 or later
• No .NET runtime - the wheel ships a self-contained native binary for your platform

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Quick Start

metaengine-openapi-httpx <input> <output> [options]

Recommended Setup

metaengine-openapi-httpx api.yaml ./generated \
  --camel-case-aliases \
  --documentation

More Examples

# From a URL
metaengine-openapi-httpx https://api.example.com/openapi.json ./generated

# Filter by OpenAPI tags
metaengine-openapi-httpx api.yaml ./generated --include-tags orders,users

# Strict spec validation + verbose logging
metaengine-openapi-httpx api.yaml ./generated --strict-validation --verbose

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CLI Options

Argument / Option	Description	Default
input (required)	OpenAPI specification file path or URL	-
output (required)	Output directory for generated Python files	-
--include-tags <tags>	Only generate operations with these tags (comma-separated)	-
--service-suffix <name>	Service class naming suffix	Service
--options-threshold <n>	Parameter count at which a method switches to an options object	4
--camel-case-aliases	Generate camelCase field aliases for Pydantic models	false
--documentation	Generate docstring comments	false
--strict-validation	Enable strict OpenAPI validation	false
--verbose	Enable verbose logging	false

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Generated Code Structure

output/
  ├── models/                    # One file per schema (Pydantic v2)
  │   ├── order.py               # class Order(BaseModel): ...
  │   ├── order_status.py        # standalone enum type
  │   └── ...
  └── services/                  # One async httpx client per tag
      ├── orders_service.py      # class OrdersService with all order operations
      └── ...

Models use Pydantic v2 (BaseModel + ConfigDict); with --camel-case-aliases, snake_case properties carry a Field(alias=...) mapping to the wire name and populate_by_name=True:

class Order(BaseModel):
    model_config = ConfigDict(populate_by_name=True)
    id: int
    customer_name: str = Field(alias='customerName')
    total_amount: float | None = Field(default=None, alias='totalAmount')

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Support

• Issues: GitHub Issues
• Email: info@metaengine.eu
• Website: metaengine.eu

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License

MIT License - see LICENSE file for details.

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About This Repository

This is the documentation and issue tracking repository for MetaEngine OpenAPI Python httpx. The package is published to PyPI.

Source code is proprietary, but the package is free to use under the MIT license.