@vielzeug/courier

Type-safe HTTP, query cache, mutations, SSE, and streaming built on native fetch.

Package: @vielzeug/courier  ·  Category: Http

Key exports: createCourier, CourierError, CourierHttpError, CourierNetworkError, CourierTimeoutError, CourierAbortError

When to use: Typed HTTP, caching, mutations, SSE, and readable streaming with a shared interceptor pipeline.

Related: @vielzeug/spell · @vielzeug/ripple · @vielzeug/vault

@vielzeug/courier is part of Vielzeug and ships as a zero-dependency TypeScript package with ESM+CJS output.

Installation

pnpm add @vielzeug/courier
npm install @vielzeug/courier
yarn add @vielzeug/courier

Quick Start

import { createCourier } from '@vielzeug/courier';

type NewUser = { name: string };
type User = { id: number; name: string };

const client = createCourier({
  baseUrl: 'https://api.example.com',
  query: { staleTime: 5_000 },
});

const userKey = ['users', 1] as const;
await client.queries.fetch({
  fetch: ({ signal }) => client.get<User>('/users/{id}', { params: { id: 1 }, signal }),
  key: userKey,
  staleTime: 5_000,
});

const nextUser = await client.mutate({
  request: ({ signal }) => client.post<User>('/users', { body: { name: 'Alice' }, signal }),
  invalidateKeys: [['users']],
});

Documentation

Full docs: https://vielzeug.dev/courier/

• Overview
• Usage Guide
• API Reference
• Examples

License

MIT © Helmuth Saatkamp — part of the Vielzeug monorepo.