rest-rpc

REST-shaped APIs with function-shaped TypeScript.

Define your HTTP API once as a shared TypeScript contract, then derive typed server handlers, fetch clients, openAPI documents, and more from it.

Features

• Shared TypeScript contracts for HTTP APIs.
• Typed server handlers for Express, Hono, Fastify, NestJS, Next.js, and Fetch runtimes.
• Typed fetch client.
• Typed TanStack Query helpers.
• Typed WebSockets, streaming, non-JSON requests/responses.
• OpenAPI documents generated from the TypeScript contract.
• Standard Schema support.

Minimal Example

Define a contract

export const api = {
	todos: {
		getById: route
			.get("/todos/:id")
			.params(z.object({ id: z.string() }))
			.response(200, z.object({ id: z.string(), title: z.string() })),
	},
};

Implement the contract on the server

const routes = router(api, {
	todos: {
		getById({ id }) {
			return getTodo(id);
		},
	},
});

registerRoutes(app, routes);

Use the contract on the client with RPC-style function calls

const client = initClient(api, {
	baseUrl: "https://api.example.com",
});

const todo = await client.todos.getById.fetch({
	id: "todo_1",
});

Documentation

Full documentation is available at rest-rpc.dev

Packages

• @rest-rpc/core: API contract, client and openAPI generation.
• @rest-rpc/express: Express server adapter.
• @rest-rpc/fastify: Fastify server adapter.
• @rest-rpc/hono: Hono server adapter.
• @rest-rpc/nest: NestJS server adapter.
• @rest-rpc/next: Next.js adapter.
• @rest-rpc/fetch: Fetch runtime adapter
• @rest-rpc/tanstack-query: TanStack Query adapter.