oRPC

oRPC is a TypeScript framework for building end-to-end typesafe APIs. Write your API once as plain TypeScript functions, and oRPC gives you a fully typed client, a REST API with an OpenAPI document, and MCP tools for AI agents, with no code generation. It runs on Node.js, Bun, Deno, Cloudflare Workers, and more.

Define procedures on the server and serve them with an RPC handler:

import { os } from '@orpc/server'
import * as z from 'zod'

export const router = {
  planet: {
    find: os
      .input(z.object({ id: z.number() }))
      .handler(({ input }) => ({ id: input.id, name: 'Earth' })),
  },
}

Then call them from a client that knows every input and output, without generating anything:

import type { RouterClient } from '@orpc/server'
import type { router } from './router'
import { createORPCClient } from '@orpc/client'
import { RPCLink } from '@orpc/client/fetch'

const link = new RPCLink({ origin: 'http://localhost:3000', url: '/rpc' })
const client: RouterClient<typeof router> = createORPCClient(link)

const planet = await client.planet.find({ id: 1 }) // { id: number, name: string }

Documentation

Read the full documentation at orpc.dev, starting with the Getting Started guide.

Packages

Core

Package	Purpose	Docs
@orpc/contract	Define API contract as the single source of truth.	Procedure Contract, Contract Router, Implementation, Generate from OpenAPI
@orpc/server	Build APIs or implement contracts.	Procedure, Router, Middleware, Context, RPC Handler
@orpc/client	Consume APIs with end-to-end type safety.	Client-Side Clients, Server-Side Clients, RPC Link, Error Handling
@orpc/openapi	Add OpenAPI compatibility to APIs.	OpenAPI Handler, OpenAPI Link, Specification, Scalar

Schema validation

Package	Purpose	Docs
@orpc/zod	JSON Schema converter for Zod.	Zod
@orpc/valibot	JSON Schema converter for Valibot.	Valibot
@orpc/arktype	JSON Schema converter for ArkType.	ArkType

Built-in features

Package	Purpose	Docs
@orpc/publisher	Pub/Sub with memory, Redis, and Upstash adapters.	Publisher
@orpc/ratelimit	Rate limiting with memory, Redis, and Upstash adapters.	Rate Limit
@orpc/experimental-lock	Locking with memory, Redis, and Upstash adapters.	Lock
@orpc/hibernation	Leverage Hibernation APIs like Cloudflare's Hibernation WebSocket.	Hibernation
@orpc/json-schema	Smart coercion for OpenAPI requests.	Smart Coercion

Framework & ecosystem integrations

Package	Purpose	Docs
@orpc/next	Integrate with Next.js Server Functions.	Next.js
@orpc/ai-sdk	Turn contracts and procedures into AI SDK tools.	AI SDK
@orpc/mcp	Expose procedures as MCP tools.	MCP
@orpc/tanstack-query	Integrate with TanStack Query.	TanStack Query
@orpc/pinia-colada	Integrate with Pinia Colada.	Pinia Colada
@orpc/swr

Observability

Package	Purpose	Docs
@orpc/opentelemetry	Integrate with OpenTelemetry for distributed tracing.	OpenTelemetry
@orpc/pino	Integrate with Pino for logging.	Pino
@orpc/evlog	Integrate with Evlog for logging.	Evlog

Sponsors

Like what we build over at middleapi? You can help keep it going through GitHub Sponsors or Open Collective. Every bit helps! 🚀

Organization Sponsors

Sponsors

Backers

With thanks to 40 past sponsors who helped get oRPC here.

Open Source Programs

middleapi is supported by these open source programs:

References

oRPC is inspired by existing solutions that prioritize type safety and developer experience. Special acknowledgments to:

• tRPC: For pioneering the concept of end-to-end type-safe RPC and influencing the development of type-safe APIs.
• ts-rest: For its emphasis on contract-first development and OpenAPI integration, which have greatly inspired oRPC's feature set.

License

Distributed under the MIT License. See LICENSE for more information.