wrpcFast, zero-dependency WebSocket RPC

Router and procedures, subscriptions with resume, rooms that scale, and binary streams with real backpressure — for Node.js and browsers, with nothing in your lockfile.

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Why wrpc?

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📭

Zero dependencies

No runtime dependencies at all — no dependencies field, no peers, no optionals. Redis, uWebSockets.js, fastify, TanStack and OpenTelemetry are injected by you, never installed by wrpc.

How injection works

🧩

Router, procedures, hooks

Declare units of procedures with access control, Standard Schema validators, timeouts and queues — and named lifecycle hooks at router, unit and procedure level instead of (ctx, next) middleware.

Write a router

🌐

Real REST, declared on the procedure

http: { method, path, status } turns a procedure into a proper endpoint: path params, /vN version paths, fastify-shaped schemas, and an OpenAPI document from wrpc types --openapi.

Declare an endpoint

🔔

Subscriptions that resume

An async generator per feed, with real backpressure. Track values with an event id and a reconnecting client replays exactly what it missed.

Push a feed

🛰️

Rooms and cluster in one

Join, leave and broadcast in one process; add any pub/sub with three methods and a room spans every instance — with presence read from a local map, fetchClients, addressed commands and node-to-node asks.

Go multi-instance

🧵

Binary streams

Upload and download bytes on the same connection, interleaved without head-of-line blocking, with backpressure that reaches all the way into TCP. 1 GiB streams at flat memory.

Move bytes

🧠

Types without a build step

Declare the contract once and connect<Api>() types every call — server-push events included — or generate it from a running server with the wrpc types CLI. No TypeScript at runtime, ever.

Type the client

🔐

Sessions and auth, batteries included

Cookie sessions by default; bearer and payload token carriers, client token stores and an authenticate/refresh lifecycle that re-presents the credential before every reconnect restore.

Wire up auth

🔌

Runs where you already run

A batteries-included server, or plug into fastify, express, bare node:http or uWebSockets.js; the same protocol rides Server-Sent Events where WebSockets cannot go — with pino-style logging and OTel traces built in.

Adapters

🌍

Node.js and the browser

One protocol implementation, under 15 KB min+gzip in a browser bundle with no Node builtins (a budget CI enforces) — plus offline through a Service Worker and TanStack Query bindings at ~1 KB.

Client guide