Using Slack with Mergify

Mergify’s Slack integration sends notifications about your development workflow directly to Slack. You can get updates about Merge Queue activities, CI job completions, test quarantine activity, and pull request events.

Before configuring specific notifications, you need to connect your Slack workspace to Mergify:

1. Go to your Mergify dashboard
2. Navigate to Integrations → Slack
3. Follow the prompts to connect your Slack workspace
4. Authorize the Mergify app for your Slack workspace

Once connected, you can configure different types of notifications based on your team’s needs.

Get real-time updates about your Merge Queue activities directly in Slack channels.

Merge Queue notifications cover:

• Pull requests entering the queue
• The queue starting and finishing checks for a pull request
• Pull requests leaving the queue, and pull requests merged out of it
• Queue pauses being created, updated, or deleted
• Scheduled freezes being created, updated, or deleted

To set up Merge Queue notifications:

1. In your Mergify dashboard, go to Integrations → Slack

2. Select the Slack channel where you want to receive Merge Queue notifications

3. Choose the repositories you want to monitor

4. Choose the events to post, or leave the list empty to post every event

5. For Checks end and Queue leave, choose the outcomes to post

Those notifications are useful for:

• Team Coordination: Keep the entire team informed about merge activities
• Release Management: Monitor critical merges during release periods
• Debugging: Quickly identify when and why queue operations fail

Two Merge Queue events, Checks end and Queue leave, can end in more than one way. Each of them gets a row under the event list, where you pick which of its outcomes post a message. The row appears when the event is selected, or when the event list is left empty to post every event. A newly selected event starts with all its outcomes selected, and the notification cannot be saved while an event has none.

The outcome of a Queue leave follows from the dequeue reason the pull request left with:

• Success: pr-merged or pr-merged-intermediate-results-skipped
• Neutral: pr-manually-merged
• Failure: any other reason

To hear only about pull requests that left the queue without being merged, select Queue leave and keep Failure as its only outcome. Each message gives the reason the pull request left. The Merged event is separate, so select it too if the channel should still hear about each merge the queue makes.

Mergify’s CI Insights can send Slack notifications about CI job completions, allowing your team to stay informed about build statuses, test failures, and deployment activities.

A CI Insights notification is posted when a job finishes, and contains:

• Job and pipeline: the job name, linked to the job in your CI, and the pipeline it belongs to

• Repository and branch: the repository, linked to GitHub, and the branch the job ran on

• Conclusion: how the job ended, with a matching emoji, when it finished, and how long it took

• Pull request: the pull request the job ran on, when there is one

• A link to CI Insights: a button opening that job’s executions in the Mergify dashboard

To configure CI Insights Slack notifications:

1. Enable CI Insights: Make sure you have CI Insights enabled for your repositories
2. Configure Notifications: In your Mergify dashboard, navigate to Integrations → Slack
3. Set Up Rules: Configure notification rules based on your criteria

You can filter notifications on:

• Repository: the repositories to watch
• Branch: the branches the job ran on
• Pipeline: the pipelines or workflows the job belongs to
• Job: the job names
• Job conclusion: action_required, cancelled, failure, neutral, skipped, success, or timed_out

Each filter is a list of exact values picked from what CI Insights has already recorded, and leaving one empty means “all”. Wildcards and patterns are not supported: a job matches only when its branch, pipeline, job name, and conclusion are among the values you selected, so a release branch has to be listed by name rather than as release/*.

Monitor failures on the main branch for production-related jobs:

• Repository: your-org/your-repo
• Branch: main
• Job conclusion: failure
• Job: deploy, security-scan, integration-tests

Monitor successes and failures on the release branches you are shipping from, each one listed by name:

• Repository: your-org/your-repo
• Branch: release/2026.1, release/2026.2
• Job conclusion: failure, success

Alert on failures of your test jobs across all branches, leaving the branch filter empty:

• Repository: your-org/your-repo
• Job conclusion: failure
• Job: unit-tests, integration-tests

1. Start Broad, Then Narrow: Begin with broader notifications and gradually add filters to reduce noise

2. Use Separate Channels: Consider different Slack channels for different types of notifications (e.g., #ci-failures, #deployments, #security-alerts)

3. Focus on Critical Paths: Prioritize notifications for jobs that affect production deployments or security

4. Monitor Flaky Tests: CI Insights notifications cannot filter on flaky tests. Use the Test Engine notifications below, which fire when a test is quarantined or unquarantined

5. Team-Specific Filters: Configure different notification rules for different teams based on their responsibilities

Mergify’s Test Engine can post a Slack message whenever a test is quarantined or unquarantined, so your team sees quarantine activity as it happens (whether a teammate acted from the dashboard or CLI, or Mergify quarantined the test automatically).

A Test Engine notification is headed either Test quarantined or Test unquarantined, and contains:

• Test: The affected test, linked to its details page

• Repository: The repository the test belongs to

• Quarantined by (or Unquarantined by): Who acted, or Mergify auto-quarantine when Mergify quarantined the test itself

• Health status: The test’s health at the time of the event

• Branch, Pipeline, and Job: The scope the quarantine covers, reading All branches, All pipelines, or All jobs where it is not narrowed. One test can be quarantined separately in several jobs, and each of those quarantines posts its own message, so these three are what tell the messages apart

• Reason: Why the test was quarantined (on quarantine events)

To configure Test Engine Slack notifications:

1. Enable Test Engine: Make sure you have Test Engine set up for your repositories

2. Connect Slack: In your Mergify dashboard, navigate to Integrations → Slack

3. Add the notification: On a channel, add a Test Engine notification, then choose the repositories to monitor and which events (Test quarantined, Test unquarantined) to subscribe to

Test Engine notifications are available on the same plans as the quarantine feature.

In addition to native Mergify notifications, you can also receive Slack notifications based on Mergify actions by using the GitHub to Slack integration.

1. Go to Slack’s GitHub Integration page

2. Click on the Add to Slack button

3. Invite the GitHub app to the channel you want. Refer to the documentation for more details

4. Make sure you subscribe to the repositories to receive the mentions as private message for the GitHub Slack app

You can use Mergify’s comment action to mention users in PR comments, which will trigger Slack notifications if the user has GitHub integrated with Slack.

Here’s an example that notifies the PR author when CI fails on hotfix PRs:

pull_request_rules:
  - name: Notify author on CI failure for hotfixes
    conditions:
      - "#check-failure > 0"
      - "label = hotfix"
    actions:
      comment:
        message: "@{{author}} :warning: The CI failed on this hotfix PR. Please review the issues and address them."

This rule:

• Checks for CI failures with #check-failure > 0
• Ensures the PR has the hotfix label
• Comments mentioning the PR author using @{{author}}
• Triggers a Slack notification if the author has GitHub-Slack integration enabled

• Critical PR Alerts: Notify authors about urgent issues with hotfix or release PRs

• Review Requests: Automatically mention reviewers when PRs are ready

• Status Updates: Keep stakeholders informed about important PR milestones

If you’re not receiving expected notifications, start with these two causes.

The channel may be disabled. Mergify stops posting to a channel it cannot reach and records when it stopped and why: either the channel’s incoming webhook is gone, or the Slack workspace revoked Mergify’s authorization. In both cases nothing arrives until the channel is connected again, and Mergify resumes on its own once it can post. The Slack configuration endpoint reports that state, and the reason, for every connected channel.

A configuration can post a test message. Each notification configuration can send a message to its channel, labeled as a test, so you can confirm delivery without waiting for a real event and without loosening your filters first.

If notifications are still missing:

1. Check Integration Status: Verify that Slack integration is properly connected in your Mergify dashboard

2. Review Notification Settings: Ensure your notification rules are correctly configured

3. Verify Channel Permissions: Make sure the Mergify Slack app has permission to post in your target channels

4. Test with Broader Filters: Temporarily use broader criteria to confirm the integration is working

5. Check Repository Access: Ensure Mergify has access to the repositories you want to monitor