Enqueue a background job to a Vercel Queues topic and process it with a push-mode consumer function

Documented steps

1. Note Vercel Queues is in Limited Beta (announced June 25, 2025; docs still use the `queue/v2beta` trigger type) — confirm account/plan access before relying on it in production.
2. Install the SDK: npm i @vercel/queue.
3. Publish a message: `import { send } from '@vercel/queue'; const { messageId } = await send('orders', { orderId, action: 'process' }, { retentionSeconds, delaySeconds, idempotencyKey });` — payload must be JSON-serializable (or use BufferTransport/StreamTransport for binary/large data).
4. Write a push-mode consumer route, e.g. `app/api/queues/process-order/route.ts`, exporting `export const POST = handleCallback(async (message, metadata) => { await processOrder(message); });` imported from `@vercel/queue`.
5. Wire the subscription in `vercel.json` by adding `"experimentalTriggers": [{ "type": "queue/v2beta", "topic": "orders" }]` to that function's entry — this is what actually makes it a consumer; the function itself has no public URL and cannot be invoked from the internet.
6. Control retry/backoff and handle poison messages via the second `handleCallback` argument's `retry(error, metadata)` callback, returning `{ afterSeconds }` to delay or `{ acknowledge: true }` to stop retrying.
7. For local development or workers running off-Vercel, use poll mode (`PollingQueueClient`) instead of a push trigger.
8. Run `vercel link` and `vercel env pull` so the SDK can authenticate to the Queues API using your project's OIDC token.
9. Official docs verified: https://vercel.com/docs/queues | https://vercel.com/docs/queues/concepts | Reference: https://vercel.com/docs/queues/sdk