trpc2openapi

Yet another tRPC to OpenAPI converter — because I couldn't find one that supported tRPC 11 and Zod 4.

This library does not modify your tRPC API in any way. It generates an OpenAPI 3.1 specification that documents your existing tRPC API as-is, conforming to the tRPC RPC specification.

Looking to make your tRPC API more RESTful? Check out trpc-to-openapi which allows you to expose your tRPC procedures as REST endpoints.

Installation

npm install trpc2openapi
# or
pnpm add trpc2openapi
# or
yarn add trpc2openapi

Usage

import { initTRPC } from '@trpc/server';
import { z } from 'zod';
import { trpc2OpenApi } from 'trpc2openapi';

const t = initTRPC.create();

const appRouter = t.router({
  greeting: t.procedure
    .input(z.object({ name: z.string() }))
    .output(z.object({ message: z.string() }))
    .query(({ input }) => ({ message: `Hello, ${input.name}!` })),
});

const openApiSpec = trpc2OpenApi({
  apiTitle: 'My API',
  apiVersion: '1.0.0',
  basePath: '/trpc',
  router: appRouter,
});

This generates an OpenAPI spec where:

• Queries become GET endpoints with input as a query parameter
• Mutations become POST endpoints with input as request body
• Responses are wrapped in tRPC's { result: { data: ... } } envelope

License

MIT