oRPC — Typesafe RPC Framework for TypeScript

Introduction

oRPC is a lightweight TypeScript RPC framework that gives you end-to-end type safety between server and client. It generates no code and requires no build step—types flow directly from your procedure definitions to your client calls.

What oRPC Does

• Provides end-to-end type inference from server procedures to client calls
• Supports input and output validation with Zod, Valibot, or any schema library
• Works with React, Vue, Svelte, SolidJS, and TanStack Query integrations
• Generates OpenAPI documentation from procedure definitions automatically
• Runs on any runtime: Node.js, Bun, Deno, Cloudflare Workers, and edge functions

Architecture Overview

oRPC defines procedures on the server with input/output schemas. The client imports the router type and uses a proxy-based client that maps function calls to HTTP requests. Type inference travels through the router type without code generation, giving autocompletion and error checking at compile time.

Self-Hosting & Configuration

• Install @orpc/server for the backend and @orpc/client for the frontend
• Define procedures with input/output schemas using Zod or Valibot
• Mount the router as an HTTP handler in Express, Hono, Next.js, or any framework
• Use the TanStack Query integration for React/Vue data fetching
• Enable OpenAPI generation with the @orpc/openapi plugin

Key Features

• Zero code generation—types flow via TypeScript inference
• Contract-first API design with optional OpenAPI spec output
• Framework-agnostic client with adapters for TanStack Query and SWR
• Middleware support for authentication, logging, and error handling
• Streaming responses and server-sent events support

Comparison with Similar Tools

• tRPC — pioneered TypeScript RPC; oRPC offers a simpler API with broader framework support
• Hono RPC — Hono-specific RPC layer; oRPC is runtime-agnostic and works with any HTTP framework
• ts-rest — contract-first REST API builder; oRPC uses RPC semantics with automatic OpenAPI output
• GraphQL — schema-based query language; oRPC provides simpler procedure calls with full type safety

FAQ

Q: How is oRPC different from tRPC? A: oRPC has a simpler API surface, supports more schema libraries, and works with more frontend frameworks out of the box.

Q: Does oRPC require code generation? A: No. Types flow via TypeScript inference—no build step or generation needed.

Q: Can I generate OpenAPI docs? A: Yes. The @orpc/openapi plugin produces OpenAPI 3.1 specs from your router definition.

Q: What runtimes does oRPC support? A: Node.js, Bun, Deno, Cloudflare Workers, and any platform with a standard Request/Response API.

Sources

• https://github.com/middleapi/orpc
• https://orpc.unnoq.com