Slack Notifications Service

The Slack Notifications Service allows your GitLab project to send events (such as issue creation) to your existing Slack team as notifications. Setting up Slack notifications requires configuration changes for both Slack and GitLab.

Note: You can also use Slack slash commands to control GitLab inside Slack. This is the separately configured Slack slash commands.

Slack configuration

  1. Sign in to your Slack team and start a new Incoming WebHooks configuration.
  2. Select the Slack channel where notifications will be sent to by default. Click the Add Incoming WebHooks integration button to add the configuration.
  3. Copy the Webhook URL, which we will use later in the GitLab configuration.

GitLab configuration

  1. Open your project’s page, and navigate to your project’s Integrations page at Settings > Integrations.
  2. Select the Slack notifications integration to configure it.
  3. Click Enable integration.
  4. In Trigger, select the checkboxes for each type of GitLab event to send to Slack as a notification. See Triggers available for Slack notifications for a full list. By default, messages are sent to the channel you configured during Slack integration.
  5. (Optional) To send messages to a different channel, multiple channels, or as a direct message:
    • To send messages to channels, enter the Slack channel names, separated by commas.
    • To send direct messages, use the Member ID found in the user’s Slack profile.
    Note: Usernames and private channels are not supported.
  6. In Webhook, provide the webhook URL that you copied from the Slack integration step.
  7. (Optional) In Username, provide the username of the Slack bot that sends the notifications.
  8. Select the Notify only broken pipelines check box to only notify on failures.
  9. In the Branches to be notified select box, choose which types of branches to send notifications for.
  10. Click Test settings and save changes.

Your Slack team will now start receiving GitLab event notifications as configured.

Triggers available for Slack notifications

The following triggers are available for Slack notifications:

  • Push: Triggered by a push to the repository.
  • Issue: Triggered when an issue is created, updated, or closed.
  • Confidential issue: Triggered when a confidential issue is created, updated, or closed.
  • Merge request: Triggered when a merge request is created, updated, or merged.
  • Note: Triggered when someone adds a comment.
  • Confidential note: Triggered when someone adds a confidential note.
  • Tag push: Triggered when a new tag is pushed to the repository.
  • Pipeline: Triggered when a pipeline status changes.
  • Wiki page: Triggered when a wiki page is created or updated.
  • Deployment: Triggered when a deployment finishes.
  • Alert: Triggered when a new, unique alert is recorded.


If your Slack integration is not working, start troubleshooting by searching through the Sidekiq logs for errors relating to your Slack service.

Something went wrong on our end

This is a generic error shown in the GitLab UI and does not mean much by itself. Review the logs to find an error message and keep troubleshooting from there.

certificate verify failed

You may see an entry similar to the following in your Sidekiq log:

2019-01-10_13:22:08.42572 2019-01-10T13:22:08.425Z 6877 TID-abcdefg ProjectServiceWorker JID-3bade5fb3dd47a85db6d78c5 ERROR: {:class=>"ProjectServiceWorker", :service_class=>"SlackService", :message=>"SSL_connect returned=1 errno=0 state=error: certificate verify failed"}

This is probably a problem either with GitLab communicating with Slack, or GitLab communicating with itself. The former is less likely since Slack’s security certificates should hopefully always be trusted. We can establish which we’re dealing with by using the below rails console script.

# start a rails console:
sudo gitlab-rails console -e production

# or for source installs:
bundle exec rails console -e production
# run this in the Rails console
# replace <SLACK URL> with your actual Slack URL
result = Net::HTTP.get(URI('https://<SLACK URL>'));0

# replace <GITLAB URL> with your actual GitLab URL
result = Net::HTTP.get(URI('https://<GITLAB URL>'));0

If GitLab is not trusting HTTPS connections to itself, then you may need to add your certificate to GitLab’s trusted certificates.

If GitLab is not trusting connections to Slack, then the GitLab OpenSSL trust store is incorrect. Some typical causes: overriding the trust store with gitlab_rails['env'] = {"SSL_CERT_FILE" => "/path/to/file.pem"}, or by accidentally modifying the default CA bundle /opt/gitlab/embedded/ssl/certs/cacert.pem.