PolyRPC

The invisible bridge between Python and TypeScript. Get tRPC-like type safety without abandoning Python.

What is PolyRPC?

PolyRPC watches your Python files and generates TypeScript types in real-time. Save your FastAPI code, get instant autocomplete in your React app.

Python (FastAPI/Pydantic) → Rust Parser (<50ms) → TypeScript Types

Install

npm install -g polyrpc

Usage

polyrpc init     # Create config file
polyrpc watch    # Watch and generate types
polyrpc generate # One-time generation

Example

Python:

class User(BaseModel):
    id: int
    name: str
    email: str

@app.get("/users/{user_id}")
def get_user(user_id: int) -> User:
    return users[user_id]

Generated TypeScript:

export interface User {
  id: number;
  name: string;
  email: string;
}

export const py = {
  users: {
    get_user: {
      query: (input: { user_id: number }) => request<User>('GET', `/users/${input.user_id}`),
    },
  },
} as const;

Usage:

const user = await py.users.get_user.query({ user_id: 1 });
// Full autocomplete, type-safe

Features

• Real-time type generation (<50ms)
• Zero build steps
• Query parameters support
• SSE/Streaming for AI apps
• Enums, unions, optionals
• Path parameters

Config

Create polyrpc.toml:

[python]
source_dir = "./backend"

[typescript]
output_file = "./frontend/src/polyrpc.ts"

[api]
base_url = "http://localhost:8000"

Packages

Package	Install
CLI	npm i -g polyrpc
Rust Core	cargo install polyrpc-sentinel
React Hooks	npm i @polyrpc/react

Docs

https://polyrpc.vercel.app

License

MIT