← Cloudflare Workers / workers / ci-cd / builds

Event subscriptions

Event subscriptions allow you to receive messages when events occur across your Cloudflare account. Cloudflare products (e.g., KV, Workers AI, Workers) can publish structured events to a queue, which you can then consume with Workers or HTTP pull consumers to build custom workflows, integrations, or logic.

For more information on Event Subscriptions, refer to the management guide.

Send build notifications

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

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

You can customize the Worker to format messages for your webhook provider. For setup instructions, refer to the 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": "[email protected]",
      "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": "[email protected]",
      "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": "[email protected]",
      "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": "[email protected]",
      "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"
  }
}