Hanzo tRPC OpenAPI

pnpm add @hanzo/trpc-openapi
# peer deps
pnpm add @trpc/server zod zod-openapi

import { initTRPC } from '@trpc/server';
import { z } from 'zod';
import { OpenApiMeta, generateOpenApiDocument, createOpenApiExpressMiddleware } from '@hanzo/trpc-openapi';
import express from 'express';

// 1. Create tRPC instance with OpenApiMeta
const t = initTRPC.meta<OpenApiMeta>().create();

// 2. Define router with openapi metadata
const appRouter = t.router({
  getUser: t.procedure
    .meta({ openapi: { method: 'GET', path: '/users/{id}' } })
    .input(z.object({ id: z.string() }))
    .output(z.object({ id: z.string(), name: z.string() }))
    .query(({ input }) => ({ id: input.id, name: 'Hanzo User' })),

  createUser: t.procedure
    .meta({ openapi: { method: 'POST', path: '/users', protect: true } })
    .input(z.object({ name: z.string(), email: z.string().email() }))
    .output(z.object({ id: z.string(), name: z.string() }))
    .mutation(({ input }) => ({ id: 'usr_new', name: input.name })),
});

// 3. Generate OpenAPI document
const openApiDoc = generateOpenApiDocument(appRouter, {
  title: 'My API',
  version: '1.0.0',
  baseUrl: 'http://localhost:3000',
});

// 4. Serve REST endpoints
const app = express();
app.get('/openapi.json', (req, res) => res.json(openApiDoc));
app.use('/api', createOpenApiExpressMiddleware({ router: appRouter }));
app.listen(3000);

┌──────────────────────┐
│  tRPC Router         │
│  (procedures + meta) │
└──────┬───────────────┘
       │
  ┌────▼────────────────────┐
  │  generateOpenApiDocument │──── OpenAPI 3.x JSON
  └────┬────────────────────┘
       │
  ┌────▼────────────────────┐
  │  HTTP Adapter            │──── REST endpoints
  │  (Express/Fastify/Next)  │     GET /users/{id}
  └─────────────────────────┘     POST /users

const doc = generateOpenApiDocument<{ isPublic: boolean }>(appRouter, {
  title: 'API',
  version: '1.0.0',
  baseUrl: 'http://localhost:3000',
  filter: ({ metadata }) => metadata.isPublic === true,
});

trpc-openapi/
├── src/
│   ├── index.ts              # Re-exports everything
│   ├── types.ts              # OpenApiMeta, OpenApiMethod, response types
│   ├── generator/
│   │   ├── index.ts          # generateOpenApiDocument()
│   │   ├── paths.ts          # OpenAPI path generation
│   │   └── schema.ts         # Zod-to-OpenAPI schema conversion
│   ├── adapters/
│   │   ├── express.ts        # Express middleware
│   │   ├── fastify.ts        # Fastify plugin
│   │   ├── next.ts           # Next.js handler (pages + app)
│   │   ├── nuxt.ts           # Nuxt handler
│   │   ├── koa.ts            # Koa middleware
│   │   ├── fetch.ts          # Fetch API handler
│   │   ├── standalone.ts     # Standalone Node HTTP
│   │   └── node-http/        # Core Node HTTP handler
│   └── utils/                # Internal utilities
├── test/
│   ├── generator.test.ts     # 115KB of generator tests
│   └── adapters/             # Adapter-specific tests
├── examples/
│   ├── with-express/
│   ├── with-fastify/
│   ├── with-nextjs/
│   ├── with-nextjs-appdir/
│   └── with-nuxtjs/
├── dist/
│   ├── cjs/                  # CommonJS build output
│   └── esm/                  # ESM build output
├── package.json              # @hanzo/trpc-openapi v0.0.17
├── tsconfig.json
└── jest.config.ts