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Slack (deprecated)

Deprecation notice

This Slack integration is deprecated and will be removed in a future release. We recommend using the new Slack App integration instead.

This feature was introduced in Unleash v3.11.0.

The Slack integration allows Unleash to post Updates when a feature flag is updated. To set up Slack, you need to configure an incoming Slack webhook URL. You can follow Sending messages using Incoming Webhooks on how to do that. You can also choose to create a slack app for Unleash, which will provide you with additional functionality to control how Unleash communicates messages on your Slack workspace.

The Slack integration will perform a single retry if the HTTP POST against the Slack Webhook URL fails (either a 50x or network error). Duplicate events may happen. You should never assume events always comes in order.



You can choose to trigger updates for the following events:

  • feature-created
  • feature-updated (*)
  • feature-metadata-updated
  • feature-project-change
  • feature-archived
  • feature-revived
  • feature-strategy-update
  • feature-strategy-add
  • feature-strategy-remove
  • feature-stale-on
  • feature-stale-off
  • feature-environment-enabled
  • feature-environment-disabled

*) Deprecated, and will not be used after transition to environments in Unleash v4.3


Unleash Slack integration takes the following parameters.

  • Slack Webhook URL - This is the only required property. If you are using a Slack Application you must also make sure your application is allowed to post to the channel you want to post to.
  • Username - Used to override the username used to post the update to a Slack channel.
  • Emoji Icon - Used to override the emoji icon used to post the update to a Slack channel.
  • Default channel - Where to post the message if the feature flags has not overridden the channel via the slack tags.

Global configuration

  • Unleash URL - The slack plugin uses the server.unleashUrl property to create the link back to Unleash in the posts. This can be set using the UNLEASH_URL environment variable or the server.unleashUrl property when starting the server from node.


The Slack integration also defined the Tag type "slack". You may use this tag to override which Slack channel Unleash should post updates to for this feature flag.

Slack Tags

In the picture you can see we have defined two slack tags for the "new-payment-system" flag. In this example Unleash will post updates to the #notifications and #random channel.