version: "1.0.1" name: queues description: Vercel Queues guidance — durable topics with at-least-once delivery, independent consumer groups, retries, delays, and idempotency keys via @vercel/queue (JS) or vercel-queue (Python). Use when deferring background work, buffering traffic, fanning out events, or choosing between Queues and Workflows. summary: "Vercel Queues (beta) publishes JSON messages to durable topics with send() from @vercel/queue; consumers are Vercel Functions exported with handleCallback() and registered in vercel.json under functions.<path>.experimentalTriggers as { type: 'queue/v2beta', topic: '<name>' }. Delivery is at-least-once with automatic retries; use Workflows instead for multi-step durable logic." metadata: priority: 6 docs:

• "https://vercel.com/docs/queues"
• "https://vercel.com/docs/queues/sdk"

sitemap: "https://vercel.com/sitemap.xml" pathPatterns:

• 'app/api/queues/**'
• 'src/app/api/queues/**'
• 'pages/api/queues/**'
• 'lib/queue.*'
• 'src/lib/queue.*'
• 'lib/queues/**'
• 'src/lib/queues/**'

bashPatterns:

• '\bnpm\s+(install|i|add)\s+[^\n]*@vercel/queue\b'
• '\bpnpm\s+(install|i|add)\s+[^\n]*@vercel/queue\b'
• '\bbun\s+(install|i|add)\s+[^\n]*@vercel/queue\b'
• '\byarn\s+add\s+[^\n]*@vercel/queue\b'
• '\b(pip|uv)\s+(install|add)\s+[^\n]*vercel-queue\b'

importPatterns:

• "@vercel/queue"

promptSignals: phrases:

• "vercel queues"
• "@vercel/queue"
• "background job"
• "background jobs"
• "message queue"
• "job queue"
• "consumer group"

allOf:

• [vercel, queues]
• [queue, topic]
• [queue, consumer]
• [queue, buffer]
• [fan, out]

anyOf:

• "queue"
• "topic"
• "retry"
• "consumer"
• "buffer"
• "background"

noneOf:

• "build queue"
• "deployment queue"
• "queued deployment"
• "deployments stuck"
• "queues up deployments"
• "queue up deployments"
• "queues my deployments"
• "queues our deployments"
• "queues your deployments"
• "queues the deployments"
• "queues deployments"
• "queues builds"
• "queues my builds"

minScore: 6 retrieval: aliases:

• queues
• message queue
• background jobs
• event streaming
• pub sub

intents:

• defer work to a queue
• process background jobs
• fan out events to consumers
• retry failed jobs
• buffer traffic spikes

entities:

• Vercel Queues
• "@vercel/queue"
• topic
• consumer group
• handleCallback
• experimentalTriggers

chainTo: - pattern: '"use workflow"|"use step"|from\s+[''"]workflow[''"]' targetSkill: workflow message: 'Workflow SDK code alongside Queues — Workflows is built on Queues and adds durable steps, sleep, and hooks. Loading Workflow guidance.' - pattern: 'from\s+''"[''"]|@aws-sdk/client-sqs' targetSkill: queues message: 'Third-party job queue detected — Vercel Queues provides durable topics with retries and fan-out without running a broker. Loading Queues guidance.' skipIfFileContains: '@vercel/queue'

Vercel Queues

You are an expert in Vercel Queues, the durable message topics that power background work and agent events on Vercel.

What It Is

Vercel Queues (public beta) gives you durable, append-only topics. Producers publish JSON messages, and every subscribed consumer group receives every message with at-least-once delivery and automatic retries. New consumer groups can join later and replay non-expired history. Queues is the primitive under Vercel Workflows; use Queues directly when you need control over publishing, consumption, and routing.

• Topic: a named durable log of messages, created on first publish
• Consumer group: an independent subscriber that receives every message on a topic
• Delivery: at-least-once; handlers must be idempotent
• Retention: 24 hours by default, up to 7 days; delivery can be delayed up to the retention period
• Modes: push (Vercel invokes your function) or poll (your own workers pull messages from any environment)

Choose Queues or Workflows

Quickstart (Next.js App Router)

Install the SDK:

npm install @vercel/queue

Publish from any route, Server Action, or function:

// app/api/orders/route.ts
import { send } from '@vercel/queue';
export async function POST(request: Request) {
  const body = await request.json();
  const { messageId } = await send('orders', { orderId: body.orderId, action: 'process' });
  return Response.json({ messageId });
}

Consume with a push-mode handler. Messages are acknowledged when the handler returns and retried when it throws:

// app/api/queues/process-order/route.ts
import { handleCallback } from '@vercel/queue';
export const POST = handleCallback(async (message, metadata) => {
  await processOrder(message);
  console.log('processed', metadata.messageId, 'delivery', metadata.deliveryCount);
});

Register the consumer in vercel.json (or vercel.ts) so Vercel routes the topic to that function:

{
  "functions": {
    "app/api/queues/process-order/route.ts": {
      "experimentalTriggers": [{ "type": "queue/v2beta", "topic": "orders" }]
    }
  }
}

Run vercel link and vercel env pull before local development so the SDK can authenticate.

Send Options

await send('orders', payload, {
  region: 'sfo1',            // target a specific region
  retentionSeconds: 3600,    // message TTL; min 60, max 604800 (7 days); default 24 hours
  delaySeconds: 60,          // delay first delivery; max 7 days, capped at the TTL
  idempotencyKey: 'order-123', // duplicates within the retention window are dropped
  headers: { 'x-trace-id': 'abc-123' },
});

Create a QueueClient when you need defaults, a fixed region, or multiple clients:

// lib/queue.ts
import { QueueClient } from '@vercel/queue';
const queue = new QueueClient({ region: 'sfo1' });
export const { send, handleCallback } = queue;

Consumer Options and Retries

handleCallback(handler, options) accepts:

Handle poison messages by acknowledging after a delivery-count threshold:

export const POST = handleCallback(processOrder, {
  retry: (error, metadata) => {
    if (metadata.deliveryCount > 5) return { acknowledge: true }; // stop retrying
    return { afterSeconds: Math.min(300, 2 ** metadata.deliveryCount * 5) };
  },
});

metadata includes messageId, deliveryCount, createdAt, expiresAt, topicName, consumerGroup, and region.

For Express, Connect, or Next.js Pages Router handlers use queue.handleNodeCallback(async (message, metadata) => ...) from a QueueClient instance, which takes (req, res).

Other Runtimes and Frameworks

• Python: vercel-queue publishes and consumes with the same topic model, and FastAPI, Flask, and Django apps can use it; Celery and Dramatiq integrations are documented under the Python backend frameworks.
• Nitro / Nuxt: declare vercel.queues.triggers in nitro.config.ts and handle messages with the vercel:queue runtime hook; send from @vercel/queue works in any server route.
• Poll mode: pull messages from your own workers in any environment when push delivery to a Vercel Function does not fit.
• Payloads: JSON by default; use BufferTransport for binary or StreamTransport for large bodies when constructing a QueueClient.

Errors

@vercel/queue exports typed errors: UnauthorizedError, BadRequestError, DuplicateMessageError (idempotency-key collision), MessageNotFoundError, and QueueEmptyError.

Common Pitfalls

1. Missing trigger: a handleCallback route with no experimentalTriggers entry never receives messages. Register every consumer in vercel.json/vercel.ts.
2. Non-idempotent handlers: delivery is at-least-once. Key side effects on metadata.messageId or your own idempotencyKey.
3. Retrying forever: without a retry policy that acknowledges poison messages, a permanently failing message is redelivered until it expires.
4. Using Queues for multi-step logic: if you need sleep, hooks, or approvals between steps, use Workflows instead of chaining topics by hand.
5. Local dev without credentials: run vercel link and vercel env pull first; otherwise send() fails with UnauthorizedError.

References

• 📖 docs: https://vercel.com/docs/queues
• 📖 JS SDK: https://vercel.com/docs/queues/sdk
• 📖 Python SDK: https://vercel.com/docs/queues/python-sdk
• 📖 poll mode: https://vercel.com/docs/queues/poll-mode
• 📖 pricing and limits: https://vercel.com/docs/queues/pricing