---
title: Event subscriptions
description: Subscribe to Workers Builds events and send notifications to Slack, Discord, or webhook endpoints.
image: https://developers.cloudflare.com/dev-products-preview.png
---

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# Event subscriptions

[Event subscriptions](https://developers.cloudflare.com/queues/event-subscriptions/) allow you to receive messages when events occur across your Cloudflare account. Cloudflare products (e.g., [KV](https://developers.cloudflare.com/kv/), [Workers AI](https://developers.cloudflare.com/workers-ai/), [Workers](https://developers.cloudflare.com/workers/)) can publish structured events to a [queue](https://developers.cloudflare.com/queues/), which you can then consume with Workers or [HTTP pull consumers](https://developers.cloudflare.com/queues/configuration/pull-consumers/) to build custom workflows, integrations, or logic.

For more information on [Event Subscriptions](https://developers.cloudflare.com/queues/event-subscriptions/), refer to the [management guide](https://developers.cloudflare.com/queues/event-subscriptions/manage-event-subscriptions/).

## Send build notifications

You can deploy a Worker that consumes build events and sends notifications to Slack, Discord, or any webhook endpoint:

[![Deploy to Cloudflare](https://deploy.workers.cloudflare.com/button)](https://deploy.workers.cloudflare.com/?url=https://github.com/cloudflare/templates/tree/main/workers-builds-notifications-template)

The template sends notifications for:

* Successful builds with preview or live deployment URLs
* Failed builds with error messages
* Cancelled builds
![Example Slack notifications for Workers Builds events](https://developers.cloudflare.com/_astro/builds-notifications-slack.rcRiU95L_169ufw.webp) 

You can customize the Worker to format messages for your webhook provider. For setup instructions, refer to the [template README ↗](https://github.com/cloudflare/templates/tree/main/workers-builds-notifications-template#readme).

## Available Workers Builds events

#### `build.started`

Triggered when a build starts.

**Example:**

```

{

  "type": "cf.workersBuilds.worker.build.started",

  "source": {

    "type": "workersBuilds.worker",

    "workerName": "my-worker"

  },

  "payload": {

    "buildUuid": "build-12345678-90ab-cdef-1234-567890abcdef",

    "status": "running",

    "buildOutcome": null,

    "createdAt": "2025-05-01T02:48:57.132Z",

    "initializingAt": "2025-05-01T02:48:58.132Z",

    "runningAt": "2025-05-01T02:48:59.132Z",

    "stoppedAt": null,

    "buildTriggerMetadata": {

      "buildTriggerSource": "push_event",

      "branch": "main",

      "commitHash": "abc123def456",

      "commitMessage": "Fix bug in authentication",

      "author": "developer@example.com",

      "buildCommand": "npm run build",

      "deployCommand": "wrangler deploy",

      "rootDirectory": "/",

      "repoName": "my-worker-repo",

      "providerAccountName": "github-user",

      "providerType": "github"

    }

  },

  "metadata": {

    "accountId": "f9f79265f388666de8122cfb508d7776",

    "eventSubscriptionId": "1830c4bb612e43c3af7f4cada31fbf3f",

    "eventSchemaVersion": 1,

    "eventTimestamp": "2025-05-01T02:48:57.132Z"

  }

}


```

#### `build.failed`

Triggered when a build fails.

**Example:**

```

{

  "type": "cf.workersBuilds.worker.build.failed",

  "source": {

    "type": "workersBuilds.worker",

    "workerName": "my-worker"

  },

  "payload": {

    "buildUuid": "build-12345678-90ab-cdef-1234-567890abcdef",

    "status": "failed",

    "buildOutcome": "failure",

    "createdAt": "2025-05-01T02:48:57.132Z",

    "initializingAt": "2025-05-01T02:48:58.132Z",

    "runningAt": "2025-05-01T02:48:59.132Z",

    "stoppedAt": "2025-05-01T02:50:00.132Z",

    "buildTriggerMetadata": {

      "buildTriggerSource": "push_event",

      "branch": "main",

      "commitHash": "abc123def456",

      "commitMessage": "Fix bug in authentication",

      "author": "developer@example.com",

      "buildCommand": "npm run build",

      "deployCommand": "wrangler deploy",

      "rootDirectory": "/",

      "repoName": "my-worker-repo",

      "providerAccountName": "github-user",

      "providerType": "github"

    }

  },

  "metadata": {

    "accountId": "f9f79265f388666de8122cfb508d7776",

    "eventSubscriptionId": "1830c4bb612e43c3af7f4cada31fbf3f",

    "eventSchemaVersion": 1,

    "eventTimestamp": "2025-05-01T02:48:57.132Z"

  }

}


```

#### `build.canceled`

Triggered when a build is canceled.

**Example:**

```

{

  "type": "cf.workersBuilds.worker.build.canceled",

  "source": {

    "type": "workersBuilds.worker",

    "workerName": "my-worker"

  },

  "payload": {

    "buildUuid": "build-12345678-90ab-cdef-1234-567890abcdef",

    "status": "canceled",

    "buildOutcome": "canceled",

    "createdAt": "2025-05-01T02:48:57.132Z",

    "initializingAt": "2025-05-01T02:48:58.132Z",

    "runningAt": "2025-05-01T02:48:59.132Z",

    "stoppedAt": "2025-05-01T02:49:30.132Z",

    "buildTriggerMetadata": {

      "buildTriggerSource": "push_event",

      "branch": "main",

      "commitHash": "abc123def456",

      "commitMessage": "Fix bug in authentication",

      "author": "developer@example.com",

      "buildCommand": "npm run build",

      "deployCommand": "wrangler deploy",

      "rootDirectory": "/",

      "repoName": "my-worker-repo",

      "providerAccountName": "github-user",

      "providerType": "github"

    }

  },

  "metadata": {

    "accountId": "f9f79265f388666de8122cfb508d7776",

    "eventSubscriptionId": "1830c4bb612e43c3af7f4cada31fbf3f",

    "eventSchemaVersion": 1,

    "eventTimestamp": "2025-05-01T02:48:57.132Z"

  }

}


```

#### `build.succeeded`

Triggered when a build succeeds.

**Example:**

```

{

  "type": "cf.workersBuilds.worker.build.succeeded",

  "source": {

    "type": "workersBuilds.worker",

    "workerName": "my-worker"

  },

  "payload": {

    "buildUuid": "build-12345678-90ab-cdef-1234-567890abcdef",

    "status": "success",

    "buildOutcome": "success",

    "createdAt": "2025-05-01T02:48:57.132Z",

    "initializingAt": "2025-05-01T02:48:58.132Z",

    "runningAt": "2025-05-01T02:48:59.132Z",

    "stoppedAt": "2025-05-01T02:50:15.132Z",

    "buildTriggerMetadata": {

      "buildTriggerSource": "push_event",

      "branch": "main",

      "commitHash": "abc123def456",

      "commitMessage": "Fix bug in authentication",

      "author": "developer@example.com",

      "buildCommand": "npm run build",

      "deployCommand": "wrangler deploy",

      "rootDirectory": "/",

      "repoName": "my-worker-repo",

      "providerAccountName": "github-user",

      "providerType": "github"

    }

  },

  "metadata": {

    "accountId": "f9f79265f388666de8122cfb508d7776",

    "eventSubscriptionId": "1830c4bb612e43c3af7f4cada31fbf3f",

    "eventSchemaVersion": 1,

    "eventTimestamp": "2025-05-01T02:48:57.132Z"

  }

}


```

```json
{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/workers/","name":"Workers"}},{"@type":"ListItem","position":3,"item":{"@id":"/workers/ci-cd/","name":"CI/CD"}},{"@type":"ListItem","position":4,"item":{"@id":"/workers/ci-cd/builds/","name":"Builds"}},{"@type":"ListItem","position":5,"item":{"@id":"/workers/ci-cd/builds/event-subscriptions/","name":"Event subscriptions"}}]}
```