Get notified when your Workers Builds complete, fail, or are cancelled. This template uses Queue Event Subscriptions to consume Workers Builds events and forward them to any webhook — Slack, Discord, or your own endpoint.

• 🔔 Real-time notifications for build success, failure, and cancellation
• 🔗 Works with any webhook (Slack, Discord, custom endpoints)
• 📋 Includes build details: project name, branch, commit, and author
• 📜 Smart error extraction for failed builds, preview URL and live deployment URL for successful builds

1. Workers Builds emits events to a Cloudflare Queue
2. This Worker consumes those events via Queue Event Subscriptions
3. Build details are formatted and sent to your configured webhook

Outside of this repo, you can start a new project with this template using C3 (the create-cloudflare CLI):

npm create cloudflare@latest -- --template=cloudflare/templates/workers-builds-notifications-template

Important: The queue must be created before deploying the worker.

1. Go to Queues
2. Click Create Queue
3. Name it builds-event-subscriptions (or your preferred name)
4. Click Create

wrangler queues create builds-event-subscriptions

Note: The queue name must match what's in wrangler.jsonc:

"queues": {
  "consumers": [
    {
      "queue": "builds-event-subscriptions",  // ← Must match your queue name
      ...
    }
  ]
}

If you use a different queue name, update wrangler.jsonc before deploying.

1. Go to Workers & Pages → Create → Import a repository
2. Connect your GitHub/GitLab and select this repository
3. Deploy

git clone https://github.com/cloudflare/templates.git
cd templates/workers-builds-notifications-template
npm install
wrangler deploy

1. Go to Slack Apps → Create New App → From scratch
2. Name it (e.g., "Workers Builds Notifications") and select your workspace
3. Go to Incoming Webhooks → Toggle On
4. Click Add New Webhook to Workspace → Select your channel
5. Copy the webhook URL

1. Go to your Discord server → Server Settings → Integrations → Webhooks
2. Click New Webhook → Select your channel
3. Copy the webhook URL
4. Append /slack to the URL (Discord supports Slack-formatted payloads)

Modify the payload format in src/index.ts to match your webhook's expected format.

1. Go to Cloudflare API Tokens
2. Click Create Token → Create Custom Token
3. Add the following permissions:
   • Workers Builds Configuration: Read
   • Workers Scripts: Read
4. Click Continue to summary → Create Token
5. Copy the token

1. Go to Workers & Pages
2. Select your deployed worker
3. Go to Settings → Variables and Secrets
4. Add:
   • SLACK_WEBHOOK_URL → Your webhook URL
   • CLOUDFLARE_API_TOKEN → Your API token

wrangler secret put SLACK_WEBHOOK_URL
# Paste your webhook URL

wrangler secret put CLOUDFLARE_API_TOKEN
# Paste your API token

Subscribe your queue to Workers Builds events.

1. Go to Queues
2. Select your queue (builds-event-subscriptions)
3. Go to the Subscriptions tab
4. Click Subscribe to events
5. Select source: Workers Builds
6. Select events: All (or specific ones)
7. Click Subscribe

wrangler queues subscription create builds-event-subscriptions \
  --source workersBuilds.worker \
  --events build.succeeded,build.failed \
  --worker-name <YOUR_CONSUMER_WORKER_NAME>

For more details, see Event Subscriptions Documentation

Trigger a build on any worker in your account. You should see a notification in your channel within seconds!

┌─────────────────┐     ┌─────────────┐     ┌──────────────────┐     ┌─────────┐
│ Workers Builds  │────▶│   Queue     │────▶│ This Consumer    │────▶│ Webhook │
│ (any worker)    │     │             │     │ Worker           │     │         │
└─────────────────┘     └─────────────┘     └──────────────────┘     └─────────┘

1. Any worker in your account triggers a build
2. Workers Builds publishes an event to your Queue
3. This consumer worker processes the event and sends a notification to your webhook

Note: Build started/queued events are acknowledged but do not send notifications.

{
	"type": "cf.workersBuilds.worker.build.succeeded",
	"source": {
		"type": "workersBuilds.worker",
		"workerName": "my-worker"
	},
	"payload": {
		"buildUuid": "build-12345678-90ab-cdef-1234-567890abcdef",
		"status": "stopped",
		"buildOutcome": "success",
		"createdAt": "2025-05-01T02:48:57.132Z",
		"stoppedAt": "2025-05-01T02:50:15.132Z",
		"buildTriggerMetadata": {
			"buildTriggerSource": "push_event",
			"branch": "main",
			"commitHash": "abc123def456",
			"commitMessage": "Fix bug in authentication",
			"author": "[email protected]",
			"repoName": "my-worker-repo",
			"providerType": "github"
		}
	},
	"metadata": {
		"accountId": "your-account-id",
		"eventTimestamp": "2025-05-01T02:48:57.132Z"
	}
}

The queue must be created before deploying. See Step 1: Create a Queue.

1. Check the queue: Dashboard → Queues → Your queue (are messages arriving?)
2. Check worker logs: Dashboard → Workers → Your consumer worker → Logs
3. Verify subscription: Dashboard → Queues → Your queue → Subscriptions tab

• Verify CLOUDFLARE_API_TOKEN is set in worker settings
• Ensure token has correct permissions (Workers Builds Configuration: Read, Workers Scripts: Read)

• Preview URL missing: Build was for main/master branch (shows Live URL instead)
• Live URL missing: Check token has correct permissions

• Queue Event Subscriptions
• Workers Builds
• Cloudflare Queues