FIFO Queues

FIFO (First-In-First-Out) queues guarantee that messages are processed in the exact order they are sent, with exactly-once delivery semantics.

Creating a FIFO Queue

Node.js SDK

const queue = await rinda.queues.create({
  name: 'payment-events',
  region: 'us-east-1',
  isFifo: true,
  dlqEnabled: true,
  maxReceiveCount: 3,
});

console.log('FIFO queue:', queue.id, queue.isFifo); // true

REST API

curl -X POST https://api.rinda.dev/v1/queues \
  -H "Authorization: Bearer $RINDA_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "payment-events",
    "region": "us-east-1",
    "isFifo": true,
    "dlqEnabled": true,
    "maxReceiveCount": 3
  }'

Message Groups

Message groups allow parallel processing while maintaining order within each group. Use groupId to assign messages to a group:

const q = rinda.queue(queue.id, { isFifo: true });

// Messages for customer-123 are processed in order
await q.send({
  body: { action: 'charge', amount: 99.99 },
  groupId: 'customer-123',
  deduplicationId: 'charge-001',
});

await q.send({
  body: { action: 'refund', amount: 99.99 },
  groupId: 'customer-123',
  deduplicationId: 'refund-001',
});

// Different group — processed independently and in parallel
await q.send({
  body: { action: 'charge', amount: 49.99 },
  groupId: 'customer-456',
  deduplicationId: 'charge-002',
});

Batch Send

Send multiple FIFO messages at once. Every message must include groupId and deduplicationId:

const q = rinda.queue(queue.id, { isFifo: true });

const result = await q.sendBatch([
  { body: { seq: 1 }, groupId: 'batch-group', deduplicationId: 'dedup-1' },
  { body: { seq: 2 }, groupId: 'batch-group', deduplicationId: 'dedup-2' },
  { body: { seq: 3 }, groupId: 'batch-group', deduplicationId: 'dedup-3' },
]);

console.log('Sent:', result.messageIds.length, 'messages');

Receiving FIFO Messages

Receive and process messages in order:

const q = rinda.queue(queue.id);

const messages = await q.receive({ maxMessages: 5 });
for (const msg of messages) {
  console.log('Body:', msg.body);
  await msg.delete();
}

Deduplication

The deduplicationId prevents duplicate messages within a 5-minute window:

await q.send({
  body: { orderId: '123' },
  groupId: 'orders',
  deduplicationId: 'order-123-created',
});

// This is a no-op — same deduplicationId within the dedup window
await q.send({
  body: { orderId: '123' },
  groupId: 'orders',
  deduplicationId: 'order-123-created',
});

SDK Validation

When you create a queue handle with { isFifo: true }, the SDK validates that groupId and deduplicationId are provided before sending:

import { RindaValidationError } from '@rindahq/sdk';

const q = rinda.queue(queue.id, { isFifo: true });

try {
  // Throws — missing groupId and deduplicationId
  await q.send({ body: { test: true } });
} catch (err) {
  if (err instanceof RindaValidationError) {
    console.error(err.message); // 'FIFO queues require "groupId"...'
  }
}

Batch validation reports the specific index:

try {
  await q.sendBatch([
    { body: { a: 1 }, groupId: 'g1', deduplicationId: 'd1' },
    { body: { b: 2 } }, // Missing groupId at index 1
  ]);
} catch (err) {
  console.error(err.message); // '...Missing on message at index 1.'
}

FIFO Queue Stats

const q = rinda.queue(queue.id);
const stats = await q.stats();
console.log('Messages:', stats.approximateMessageCount);

When to Use FIFO

Use Case	Queue Type
Event processing where order matters	FIFO
Financial transactions	FIFO
State machine updates	FIFO
Log ingestion	Standard
Email notifications	Standard
Thumbnail generation	Standard

Limitations

• FIFO queues have lower throughput than standard queues (300 messages/second per group)
• Both groupId and deduplicationId are required for every message
• Deduplication window is 5 minutes