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What is the Trigger Inbox API?

The Trigger Inbox API lets you receive and process events from apps connected to Zapier. Instead of setting up webhooks or building your own polling system for each app, you create an inbox that subscribes to trigger events, and the API delivers messages to you. The queue model follows the same pull-based, at-least-once delivery pattern as Amazon SQS. Your backend pulls (leases) messages on its own schedule, processes them, and acknowledges (deletes) them. If you have used SQS, the concepts map closely.

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Key benefits

• One API for all apps: Gmail, Slack, GitHub, Google Calendar, and 9,000+ apps.
• Managed authentication: Zapier handles OAuth flows and token refresh.
• Reliable delivery: Messages are queued and can be retried.
• Standard format: Consistent message structure across all apps.
• No inbound endpoints: Your backend pulls messages on its own schedule. You do not need to expose a public webhook endpoint to receive events.
• Concurrency-safe: Designed to be consumed by multiple processes, with built-in leasing and acknowledgment modeled on SQS.

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Core concepts

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How it works

1. Create an inbox. Subscribe to a trigger (for example, Gmail “new email”).
2. Event occurs. A user receives an email; Gmail fires the trigger.
3. Message queued. Zapier captures the event and adds it to your inbox.
4. Lease available messages. Your app requests a batch of messages for exclusive processing.
5. Process. Read the payload and run your business logic.
6. Acknowledge. Confirm success; the message is permanently removed.

If you set a notification_url, Zapier also sends a POST to your server when new messages arrive, so you can lease on demand instead of polling continuously. The Trigger Inbox API uses an at-least-once delivery model, the same guarantee Amazon SQS provides:

• Messages are delivered at least once (possibly more if retries occur).
• You must implement idempotent processing (safe to process duplicates).
• Messages not acknowledged within the lease duration return to the queue.
• Messages that are leased 5 times without being acknowledged are quarantined.

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Architecture

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Inbox states

An inbox transitions through these states:

• Initializing: Subscription is being set up.
• Active: Receiving events and queueing messages.
• Paused: Collection stopped. Buffered messages are preserved. Check the paused_reason field for detail. Resuming a paused inbox goes back through initializing.
• Deleting: Being torn down asynchronously (takes several hours to complete).
• Initialization failure: Setup failed. Check paused_reason for detail. You cannot resume from this state. Delete the inbox and create a new one.

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Message lifecycle

Messages flow through these states:

• Available: Ready to be leased.
• Leased: Locked by a consumer for a set duration.
• Acknowledged: Permanently removed.
• Expired: Lease timed out; message returns to available.
• Quarantined: Leased and released 5 times without acknowledgment. No longer returned by lease calls, but visible in list calls for inspection.

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When to use the Trigger Inbox API

The Trigger Inbox API is a good fit when you need programmatic, backend access to events from multiple apps, without building per-app webhook integrations, polling infrastructure, or exposing public endpoints. Use it if you are:

• Processing events from multiple apps (Gmail, Slack, GitHub) through a single API
• Building data pipelines or internal tools that consume events programmatically
• Working in infrastructure that cannot expose public webhook endpoints
• Decoupling event capture from processing, or batching events before acting on them

It is not the right fit if you need sub-second event delivery. The API uses a queued, pull-based model and is not designed for real-time streaming.

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Comparison to Powered by Zapier

If you want end users to build their own workflows, Powered by Zapier is the better fit. The two approaches serve different audiences:

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Security and authentication

The Trigger Inbox API uses OAuth 2.0 bearer tokens for authentication. All API requests must include an Authorization: Bearer YOUR_ACCESS_TOKEN header. Two authentication methods are available:

• SDK client credentials: Quick setup for local testing.
• JWT authentication: Production-ready with user-specific tokens.

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Limits

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Next steps

1. Trigger Inbox onboarding: the fastest way to understand the message queue model, no external app connection required.
2. Create a trigger inbox for an app: connect to Slack, Gmail, and 9,000+ other apps.
3. Manage your inbox.
4. Trigger Inbox API reference.