Cloudflare Queues limits vs Sume queue_full 429: who retries?

When a Cloudflare Queues consumer calls Sume and gets 429, let the queue do the waiting: retry the message with a delaySeconds value instead of sleeping inside the consumer. Cloudflare allows delaySeconds up to 24 hours, 100 retries and a 15 minute consumer wall time. Sume returns 429 queue_full or 429 rate_limited, and 402 insufficient_credits, and these three need different handling.

Limits on both sides

Values for Cloudflare are from its Queues limits page. Sume values are from its generation admission docs.

Handle the three 429 and 402 cases differently

rate_limited carries a retry-after hint, so use it as the delaySeconds. queue_full means your account's queue capacity, max(3, 5 times concurrency), is occupied. Retrying immediately only adds noise, so use a longer delay and fewer attempts. insufficient_credits is not transient: do not retry, alert a person.

Sume's concurrency is set by plan, so a Cloudflare queue that fans out wider than your concurrency will mostly produce waits. Treat the wave_size_hint in the generation_limits snapshot as a hint, not a guarantee.

• 429 rate_limited: message.retry({delaySeconds}) using retry-after.
• 429 queue_full: retry with a larger delay and cap attempts.
• 402 insufficient_credits: ack the message and page someone.
• Success 202: ack, and store the job id.

Keep retries from duplicating paid jobs

A queue redelivers on any consumer failure, including a crash after Sume accepted the request. Use the message id or your business id as the Idempotency-Key. A repeat with the same key and body returns the original job; a different body returns 409 idempotency_conflict, which tells you a producer bug changed the payload.

When to use bulk runs instead

If the messages are many items of one Format, one POST /v1/formats/{handle}/{slug}/bulk-runs takes up to 100 items with a concurrency setting and returns 202 with a queue you read at GET /v1/format-run-queues/{id}. A replayed key returns the old queue. Webhooks fire per item, not per queue.