Introduction

REST-shaped APIs with function-shaped TypeScript.

rest-rpc lets you define HTTP routes in a shared TypeScript contract, then use that contract to derive typed server handlers, typed fetch clients, TanStack Query options, and OpenAPI documents.

The API stays REST-shaped. Everyday application code can feel like function calls.

const todo = await api.todos.get.fetch({ id: "todo_1" });

That call is still a normal HTTP request:

GET /todos/todo_1

The Shape

HTTP details live in the contract.

export const api = router({
	todos: {
		get: {
			method: "GET",
			path: "/todos/:id",
			request: {
				params: {
					id: z.string(),
				},
			},
			responses: {
				200: todoSchema,
				404: z.object({
					code: z.literal("TODO_NOT_FOUND"),
				}),
			},
		},
	},
});

Handlers and clients use the route tree as typed functions.

const routes = router(api, {
	todos: {
		get({ id }) {
			const todo = todos.get(id);

			if (!todo) {
				return {
					status: 404,
					body: { code: "TODO_NOT_FOUND" },
				};
			}

			return todo;
		},
	},
});

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

Why rest-rpc?

• Contract-first REST without tying the API to one server framework.
• Elegant RPC-style calls and handlers without losing REST semantics.
• Flatter handler and client calls because request locations live in the contract.
• Typed status responses when you need them, and direct response bodies when you don’t.
• Runtime validation through Standard Schema-compatible libraries.
• Thin Express, Hono, and Fastify adapters for typed server handlers.
• Typed TanStack Query options and query keys over the same contract.
• OpenAPI document generation.

Small By Design

rest-rpc focuses on the API boundary: routes, request validation, typed handlers, typed clients, status-aware responses, TanStack Query options, and OpenAPI document generation.

It does not replace middleware, authentication, dependency injection, database access, file storage, OpenAPI UI, deployment, or frontend state management. Those concerns stay in your application and framework code the way you already know them.

Start Here

• Quickstart builds the first route end to end.
• Comparison compares rest-rpc with other TypeScript REST/RPC libraries.
• Concepts explains the mental model.
• Contract covers route declarations.
• Responses covers status-keyed responses.
• OpenAPI covers document generation.