fastapi-jsonrpc¶

JSON-RPC 2.0 server built on top of FastAPI. Write JSON-RPC methods the same way you write FastAPI endpoints — with Pydantic models, dependency injection, typed parameters and async support — and get OpenAPI, Swagger UI and OpenRPC for free.

import fastapi_jsonrpc as jsonrpc
from fastapi import Body

app = jsonrpc.API()
api_v1 = jsonrpc.Entrypoint('/api/v1/jsonrpc')


@api_v1.method()
def echo(data: str = Body(..., examples=['hello'])) -> str:
    return data


app.bind_entrypoint(api_v1)

Run it with uvicorn and open:

• POST /api/v1/jsonrpc — JSON-RPC endpoint
• GET /docs — Swagger UI
• GET /openapi.json — OpenAPI schema
• GET /openrpc.json — OpenRPC schema

Why fastapi-jsonrpc¶

• All of FastAPI. Depends, Body, Header, Cookie, Pydantic models, async/await, lifespans, background tasks — everything works the same way inside a JSON-RPC method.
• Auto-generated schemas. Each method appears as a regular POST route in the OpenAPI schema, so Swagger UI lets you call methods interactively. OpenRPC schema is generated alongside.
• Typed error model. Errors are plain Python classes with a CODE, MESSAGE and an optional Pydantic DataModel. They end up in the schema automatically.
• Batch requests & notifications. Full JSON-RPC 2.0 support — batches, notifications, per-request dependencies.
• JSON-RPC middlewares. Context manager based middlewares with access to the raw request, the raw response and the exception (if any).
• Sentry integration. Optional integration that reports the JSON-RPC method name as the transaction and keeps one Sentry transaction per batch with a span per method.

Where to start¶

• Installation — install the package.
• Quickstart — a minimal working example in under a minute.
• Methods & parameters — how to declare JSON-RPC methods.
• Errors — custom errors with typed DataModel.
• Dependencies — reuse FastAPI dependencies, including per-batch and per-request.
• Middlewares — cross-cutting concerns around every call.
• OpenAPI & OpenRPC — schemas and interactive docs.
• Sentry — tracing and error reporting.