RateLimit

Source: src/Cloudflare/Workers/RateLimit.ts

A Cloudflare Rate Limit binding for counting arbitrary keys inside Workers — a Worker-only binding with no backing cloud resource.

RateLimit is a single value that is at once the Binding.Service tag, the callable that produces a {@link RateLimitBinding}, and the type. Declare it on a Worker’s env (it flows through InferEnv → the native cf.RateLimit) or yield* it inside an Effect-native Worker to attach the binding and obtain the {@link RateLimitClient}.

Declaring on a Worker’s env

export const Worker = Cloudflare.Worker("Worker", {
  main: "./src/worker.ts",
  env: {
    THROTTLE: Cloudflare.RateLimit("THROTTLE", {
      namespaceId: 1001,
      simple: { limit: 10, period: 60 },
    }),
  },
});

export type WorkerEnv = Cloudflare.InferEnv<typeof Worker>;
//   { THROTTLE: RateLimit } — the native Cloudflare binding

// worker.ts
export default {
  fetch: async (req: Request, env: WorkerEnv) => {
    const { success } = await env.THROTTLE.limit({ key: "ip" });
    return new Response(success ? "ok" : "rate limited");
  },
};

Binding inside an Effect-native Worker

Cloudflare.Worker("Worker", { main: "./src/worker.ts" },
  Effect.gen(function* () {
    // Attaches the binding to this Worker AND returns the runtime client.
    const throttle = yield* Cloudflare.RateLimit("THROTTLE", {
      namespaceId: 1001,
      simple: { limit: 10, period: 60 },
    });

    return {
      fetch: Effect.gen(function* () {
        const { success } = yield* throttle.limit({ key: "ip" });
        return HttpServerResponse.text(success ? "ok" : "rate limited");
      }),
    };
  }).pipe(Effect.provide(Cloudflare.Workers.RateLimitBinding)),
);