Slack Notification Setup

Receive alerts directly in your Slack channel when monitors go down or recover.

Prerequisites

  • A Slack workspace where you have permission to add apps
  • A Slack channel where you want to receive alerts

Step 1: Create an Incoming Webhook in Slack

  1. Go to Slack API: Incoming Webhooks
  2. Click Create your Slack app (or use an existing app)
  3. Select From scratch
  4. Enter an app name (e.g., “Monitoring Alerts”) and select your workspace
  5. Click Create App
  6. In the left sidebar, click Incoming Webhooks
  7. Toggle Activate Incoming Webhooks to On
  8. Click Add New Webhook to Workspace
  9. Select the channel where you want to receive alerts
  10. Click Allow
  11. Copy the webhook URL that appears - you’ll need this in the next step

The webhook URL will look like this:

https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX

Step 2: Add the Webhook to Your Account

  1. Log in to your monitoring dashboard
  2. Go to Settings in the navigation menu
  3. Click the Slack tab
  4. Click + Add Webhook
  5. Enter a friendly name for this webhook (e.g., “Production Alerts” or “#ops-channel”)
  6. Paste the webhook URL you copied from Slack
  7. Ensure Active is checked
  8. Click Add Webhook

You can test the webhook by clicking the Test button. A test message will be sent to your Slack channel.

Step 3: Assign the Webhook to Monitors

  1. Go to Monitors in the navigation menu
  2. Click on a monitor you want to receive alerts for
  3. Click the Notifications tab
  4. In the Slack Webhooks section, select your webhook from the dropdown
  5. Click Add

Repeat this for each monitor you want to receive Slack alerts for.

Alert Types

You’ll receive notifications for:

  • Down alerts: When a monitor fails (HTTP errors, SSL certificate issues, domain expiration warnings)
  • Recovery alerts: When a monitor recovers after being down

Each alert includes:

  • Monitor name
  • URL or domain being monitored
  • Error details (for down alerts)
  • Downtime duration (for recovery alerts)
  • Timestamp
  • Link to view the monitor in your dashboard

Managing Webhooks

Edit a Webhook

  1. Go to Settings > Slack
  2. Find the webhook you want to edit
  3. Click Edit
  4. Make your changes and click Save

Disable a Webhook

You can temporarily disable a webhook without deleting it:

  1. Go to Settings > Slack
  2. Find the webhook you want to disable
  3. Click Edit
  4. Uncheck Active
  5. Click Save

Disabled webhooks won’t receive any notifications until re-enabled.

Delete a Webhook

  1. Go to Settings > Slack
  2. Find the webhook you want to delete
  3. Click Delete
  4. Confirm the deletion

Deleting a webhook will remove it from all monitors it was assigned to.

Troubleshooting

Test message not arriving

  1. Verify the webhook URL is correct and complete
  2. Check that the webhook is marked as Active
  3. Ensure the Slack app still has access to the channel
  4. Try creating a new webhook in Slack and updating the URL

Alerts not being sent

  1. Check that the webhook is assigned to the monitor
  2. Verify the webhook is Active in Settings
  3. Check if you’ve exceeded your notification quota
  4. Ensure the monitor has alerting enabled

Webhook URL rejected

The webhook URL must match the Slack format:

https://hooks.slack.com/services/[TEAM_ID]/[APP_ID]/[TOKEN]

Make sure you copied the complete URL including all three path segments.

Channel was deleted or renamed

If the Slack channel associated with a webhook is deleted:

  1. Create a new incoming webhook for the new channel in Slack
  2. Update the webhook URL in Settings

Multiple Channels

You can create multiple webhooks to send alerts to different Slack channels:

  • Create separate webhooks for different teams or severity levels
  • Assign different webhooks to different monitors
  • A single monitor can have multiple webhooks assigned

Example setup:

  • #ops-critical - Production monitors
  • #ops-warnings - SSL and domain expiration warnings
  • #dev-alerts - Development/staging monitors

Security Notes

  • Webhook URLs contain authentication tokens - treat them as secrets
  • Don’t share webhook URLs publicly or commit them to source control
  • If a webhook URL is compromised, delete it in Slack and create a new one
  • Rotate webhooks periodically as a security best practice
  • Consider using private channels for sensitive alerts

Customizing the Slack App

You can customize how alerts appear in Slack:

  1. Go to Your Slack Apps
  2. Select your monitoring app
  3. Click Basic Information in the sidebar
  4. Scroll to Display Information
  5. Update the app name, icon, and description
  6. Click Save Changes

This affects how the bot appears when posting messages to your channels.