OpenAPI HTTPX

Generate a typed HTTPX client from an OpenAPI specification.

openapi-httpx is a thin wrapper around the HTTPX Client class. For each operation in your OpenAPI spec it emits an @overload on the client and TypedDicts for the parameters, request body, and response — so your editor and type checker know exactly which paths, params, and payloads are valid.

Prior art

Inspired by openapi-fetch for TypeScript.

Built on datamodel-code-generator, which does the heavy lifting of parsing the spec and emitting types. openapi-httpx extends it with an httpx.Client subclass and per-operation @overloads.

Install

pipuvPoetry

pip install openapi-httpx

uv add openapi-httpx

poetry add openapi-httpx

httpx is a runtime dependency

The generated client imports httpx when you run it, but openapi-httpx doesn't pull it in for you (it's only needed at generation time on the dev side). Make sure any environment that runs the client has httpx installed: pip install httpx (or uv add httpx / poetry add httpx).

Quick start

Start with an OpenAPI spec:

demo.yaml

openapi: 3.1.0
info: { title: Demo, version: 0.1.0 }
paths:
  /users/{id}:
    get:
      operationId: getUserById
      parameters:
        - { name: id, in: path, required: true, schema: { type: string } }
      responses:
        "200":
          description: OK
          content:
            application/json:
              schema:
                type: object
                required: [id, name]
                properties:
                  id: { type: string }
                  name: { type: string }

Generate a client:

openapi-httpx --input demo.yaml --output demo_client.py

Use it like httpx.Client, but with full type inference on every call:

from demo_client import OpenApiClient

with OpenApiClient(base_url="https://api.example.com") as client:
    user = client.GET("/users/{id}", params={"id": "abc"})
    print(user["name"])  # str

That's it. The client is a regular httpx.Client, so everything you already know about HTTPX (timeouts, auth, event hooks, retries, custom transports) still applies.

Where to next

• Using the client — how the generated methods differ from plain HTTPX: path params, request bodies, response parsing, errors, async.
• Reference — every CLI flag and the Python API for programmatic use.