Queue Trigger

Paid Feature - Queue triggers are available on the Hobby and Pro plans. View pricing

The queue trigger enables asynchronous message processing. Flows with queue triggers act as message handlers that process work from a queue with automatic retries and backoff policies.

Configuration

{
  "trigger": {
    "type": "queue",
    "config": {
      "name": "order-processing",
      "parallelism": 1,
      "retries": 5,
      "timeout": "30s",
      "backoff": {
        "strategy": "exponential",
        "initial": "1s",
        "max": "1h"
      }
    }
  }
}

Config Fields

Field	Type	Required	Default	Description
`name`	string	Yes	-	Queue name (unique per project)
`parallelism`	number	No	`1`	Number of concurrent consumers (1 = strict FIFO)
`retries`	number	No	`0`	Maximum retry attempts on failure (0 = no retries)
`timeout`	string	No	`"30s"`	Handler execution timeout
`backoff`	object	No	-	Retry backoff strategy (only used when retries > 0)

Queue Names

Queue names must be unique within your project. Choose descriptive names that reflect the purpose:

order-processing
email-notifications
payment-webhooks
data-sync

Parallelism

Controls how many messages can be processed concurrently.

Setting	Behavior
`parallelism: 1`	Strict FIFO ordering - one message at a time
`parallelism: 5`	Up to 5 messages processed concurrently

Use parallelism: 1 when order matters. Use higher values for independent operations like sending notifications.

Retries

By default, retries are disabled. Set retries to enable automatic retry on failure.

// No retries - fail immediately on error
{ "retries": 0 }

// Retry up to 5 times
{ "retries": 5 }

// Retry up to 10 times with backoff
{ "retries": 10, "backoff": { "strategy": "exponential", "initial": "2s", "max": "30m" } }

Backoff Strategies

Only applicable when retries > 0. Configure how long to wait between retry attempts.

Exponential Backoff

Delays grow exponentially: 1s, 2s, 4s, 8s, 16s… capped at max.

{
  "backoff": {
    "strategy": "exponential",
    "initial": "1s",
    "max": "1h"
  }
}

Linear Backoff

Delays grow linearly: 5s, 10s, 15s, 20s… capped at max.

{
  "backoff": {
    "strategy": "linear",
    "initial": "5s",
    "max": "5m"
  }
}

Fixed Backoff

Constant delay between retries. Useful for rate-limited APIs.

{
  "backoff": {
    "strategy": "fixed",
    "delay": "60s"
  }
}

Duration Format

Durations can be specified as strings or milliseconds: String format:

Format	Example	Description
`Xs`	`"30s"`	Seconds
`Xm`	`"5m"`	Minutes
`Xh`	`"1h"`	Hours

Milliseconds:

Example	Equivalent
`2000`	2 seconds
`60000`	1 minute
`3600000`	1 hour

Both formats are valid:

// String format
{ "timeout": "30s", "backoff": { "initial": "2s", "max": "1h" } }

// Milliseconds
{ "timeout": 30000, "backoff": { "initial": 2000, "max": 3600000 } }

// Mixed
{ "timeout": "30s", "backoff": { "initial": 2000, "max": "1h" } }

Runtime Context

When your handler flow executes, the context includes message information:

{
  "trigger": {
    "type": "queue",
    "config": {
      "name": "order-processing",
      "parallelism": 1,
      "retries": 5,
      "timeout": "30s",
      "backoff": { ... }
    },
    "message": {
      "id": "msg_xxx",
      "retried": 0
    },
    "body": {
      "order_id": "123",
      "action": "process"
    }
  }
}

Context References

Reference	Description
`{{trigger.config.name}}`	Queue name
`{{trigger.message.id}}`	Unique message ID
`{{trigger.message.retried}}`	Number of retry attempts (0 on first try)
`{{trigger.body}}`	Message payload
`{{trigger.body.order_id}}`	Access message fields directly

Example: Check Retry Count

{
  "id": "check_retry",
  "type": "condition",
  "config": {
    "conditions": [
      {
        "if": "{{trigger.message.retried}} >= 3",
        "then": ["send_alert"]
      }
    ],
    "else": ["process_normally"]
  }
}

Failure Handling

Scenario	Behavior
`retries = 0`	Message fails immediately and moves to Dead Letter Queue (DLQ)
`retries > 0`	Message is retried with configured backoff until success or retries exhausted
Retries exhausted	Message moves to Dead Letter Queue (DLQ)

Failed messages in the DLQ can be viewed, retried, or deleted via the API.

Complete Example

A queue handler that processes orders:

{
  "name": "Order Processing Handler",
  "trigger": {
    "type": "queue",
    "config": {
      "name": "order-processing",
      "parallelism": 1,
      "retries": 5,
      "timeout": "30s",
      "backoff": {
        "strategy": "exponential",
        "initial": "2s",
        "max": "10m"
      }
    }
  },
  "nodes": [
    {
      "id": "log_start",
      "type": "set",
      "config": {
        "key": "order_id",
        "value": "{{trigger.body.order_id}}"
      }
    },
    {
      "id": "fetch_order",
      "type": "http",
      "config": {
        "method": "GET",
        "url": "https://api.example.com/orders/{{order_id}}"
      }
    },
    {
      "id": "process_payment",
      "type": "http",
      "config": {
        "method": "POST",
        "url": "https://api.stripe.com/v1/charges",
        "headers": {
          "Authorization": "Bearer {{env.STRIPE_KEY}}"
        },
        "body": {
          "amount": "{{fetch_order.output.body.total}}",
          "currency": "usd"
        }
      }
    },
    {
      "id": "update_status",
      "type": "http",
      "config": {
        "method": "PATCH",
        "url": "https://api.example.com/orders/{{order_id}}",
        "body": {
          "status": "paid",
          "charge_id": "{{process_payment.output.body.id}}"
        }
      }
    },
    {
      "id": "respond",
      "type": "response",
      "config": {
        "status": 200,
        "body": {
          "success": true,
          "order_id": "{{order_id}}"
        }
      }
    }
  ]
}

Sending Messages to Queues

Use the enqueue node to send messages to queue handlers:

{
  "id": "queue_order",
  "type": "enqueue",
  "config": {
    "handler": "order-processing-handler",
    "message": {
      "order_id": "{{request.body.order_id}}"
    }
  }
}

Use Cases

Order Processing

Process orders asynchronously to return fast API responses:

HTTP endpoint receives order
Validates and accepts order immediately (returns 202)
Enqueues order for background processing
Queue handler processes payment, updates inventory, sends confirmation

Webhook Processing

Handle incoming webhooks reliably:

Webhook arrives at HTTP endpoint
Enqueue webhook payload for processing
Return 200 immediately
Queue handler processes webhook with retries

Batch Operations

Process large datasets item by item:

Upload triggers batch job
Each item is enqueued separately
Queue handler processes items with parallelism
Failed items retry automatically

Email Notifications

Send emails without blocking API responses:

User action triggers notification
Email data is enqueued
Queue handler sends email via email service
Retries handle temporary failures

Plan Availability

Queue triggers are available on Hobby and Pro plans.

Enqueue Node - Send messages to queue handlers
HTTP Trigger - Create REST endpoints
Cron Trigger - Schedule flows

Getting Started

Triggers

Nodes

Reference

Configuration

Config Fields

Queue Names

Parallelism

Retries

Backoff Strategies

Exponential Backoff

Linear Backoff

Fixed Backoff

Duration Format

Runtime Context

Context References

Example: Check Retry Count

Failure Handling

Complete Example

Sending Messages to Queues

Use Cases

Order Processing

Webhook Processing

Batch Operations

Email Notifications

Plan Availability

​Configuration

​Config Fields

​Queue Names

​Parallelism

​Retries

​Backoff Strategies

​Exponential Backoff

​Linear Backoff

​Fixed Backoff

​Duration Format

​Runtime Context

​Context References

​Example: Check Retry Count

​Failure Handling

​Complete Example

​Sending Messages to Queues

​Use Cases

​Order Processing

​Webhook Processing

​Batch Operations

​Email Notifications

​Plan Availability

​Related

Configuration

Config Fields

Queue Names

Parallelism

Retries

Backoff Strategies

Exponential Backoff

Linear Backoff

Fixed Backoff

Duration Format

Runtime Context

Context References

Example: Check Retry Count

Failure Handling

Complete Example

Sending Messages to Queues

Use Cases

Order Processing

Webhook Processing

Batch Operations

Email Notifications

Plan Availability

Related