Callspec

1. Define once

   export const searchPosts = route({
     input: query,
     output: results,
     handler: async (input, ctx) => {
       // your logic
     },
   })
   
   export const api = spec({
     routes: {searchPosts},
   })

2. Serve it all

   • HTTP RPC/v1/*
   • Docs UI/docs
   • OpenAPI/openapi.json
   • MCP/mcp

   Auth, typed errors & logging

3. TypeScript SDK

   $npx callspec

   ↓

   

   api.searchPosts({…})generated/api.ts

4. OpenAPI anywhere

   

   Multi-language SDKs & docs from your OpenAPI

   • Python
   • Go
   • Java
   • C#

• Errors done right

  Every error has a code, a type, and a shape. No more guessing.

• No drift

  Client and server stay in sync automatically.

• End-to-end types

  From server to SDK to docs to clients.

• Works with the ecosystem

  Plays well with your favorite tools.

Try it locally

Run the Chirp API explorer

Clone the repo and start the sample API — interactive docs UI, MCP connect flow, and the same Callspec explorer your APIs get.

npm run build && npm run serve:chirp-demo

Then open http://127.0.0.1:3456/v1/docsBearer token demo

Full steps→