Produce and consume messages with Cloudflare Queues including retry configuration

Verified steps

1. Create a Queue in the Cloudflare dashboard or with wrangler queues create <queue-name>; bind it as a producer in wrangler.toml under [[queues.producers]] (gives env.QUEUE.send() in Workers) and as a consumer under [[queues.consumers]] with your Worker script
2. Send a single message from a Worker with await env.QUEUE.send(body) where body can be a string, ArrayBuffer, or JSON-serializable object; use env.QUEUE.sendBatch(messages) to send up to 100 messages in one call, each message being an object with a body field
3. The consumer Worker receives a MessageBatch parameter in its queue handler: export default { async queue(batch, env) { for (const msg of batch.messages) { ... msg.ack(); } } }; call msg.ack() after successful processing or msg.retry() to requeue
4. Configure retry behavior in wrangler.toml under the consumer binding: set max_retries (default 3) and dead_letter_queue to the name of another Queue that receives messages exhausting their retry budget
5. Set max_batch_size (up to 100) and max_batch_timeout (seconds) on the consumer to control how often and how many messages are delivered per invocation; larger batches reduce Worker invocation overhead
6. For delayed retries, call msg.retry({ delaySeconds: n }) to requeue the message with a specific delay rather than immediate redelivery; this allows exponential backoff patterns