Rate Limit

Throttle outbound messages locally with a token bucket.

pnpm add @postbote/plugin-rate-limit

import { rateLimit } from "@postbote/plugin-rate-limit";

const mailer = createPostbote({
  adapter,
  plugins: [rateLimit({ tokens: 10, intervalMs: 1_000 })],
});

The bucket starts full, allowing a burst of tokens sends. Later sends wait for continuous token refills. Set mode: "reject" to immediately throw a retryable RATE_LIMITED error instead. Waiting observes the send's AbortSignal.

Place rate limiting outside failover() to limit logical sends. Put it inside failover only when each provider attempt should consume a token.