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Integrate with mailcow

Support level: Community

What is mailcow?​

mailcow is a Dockerized, open-source groupware and email suite based on Docker. It relies on many well-known and long-used components, which, when combined, result in a comprehensive email server solution.

-- https://mailcow.email/

Preparation​

The following placeholders are used in this guide:

  • mailcow.company is the FQDN of the mailcow installation.
  • authentik.company is the FQDN of the authentik installation.
info

This documentation lists only the settings that you need to change from their default values. Be aware that any changes other than those explicitly mentioned in this guide could cause issues accessing your application.

authentik configuration​

Redirect URI changes in authentik 2026.5

In authentik versions earlier than 2026.5, all Redirect URIs are automatically treated as Authorization type. If you are using one of these older authentik versions, add only the Authorization URL to your Redirect URIs and do not configure a Post Logout URI.

To support the integration of mailcow with authentik, you need to create property mappings, set user attributes, and create an application/provider pair in authentik.

Create property mappings​

mailcow requires users to have an email address. The custom email scope mapping returns the email_verified claim from a user attribute, and the mailcow_template scope mapping lets mailcow select a mailbox template when creating or updating mailboxes.

  1. Log in to authentik as an administrator and open the authentik Admin interface.

  2. Navigate to Customization > Property Mappings and click New Property Mapping.

  3. Select Scope Mapping as the property mapping type. Use email as the scope name, and copy the user attribute expression from Email scope verification.

  4. Click Create.

  5. Create another Scope Mapping using the following values:

    • Name: mailcow_template

    • Scope name: mailcow_template

    • Expression:

      return {
          "mailcow_template": request.user.attributes.get("mailcow_template", "default"),
      }

  6. Click Create.

Set user attributes​

  1. Log in to authentik as an administrator and open the authentik Admin interface.

  2. Navigate to Directory > Users and select a user that will use the mailcow integration.

  3. Click Edit User.

  4. Add the following attributes to the Attributes field:

    email_verified: true
    mailcow_template: default

  5. Click Save Changes.

Repeat these steps for all users that need to use the mailcow integration. The user's email address in authentik must match the mailcow mailbox address for existing mailboxes. If mailcow creates the mailbox during first login, the email domain must already exist in mailcow.

Create an application and provider​

  1. Log in to authentik as an administrator and open the authentik Admin interface.

  2. Navigate to Applications > Applications and click New Application to open the application wizard.

    • Application: provide a descriptive name, an optional group for the type of application, the policy engine mode, and optional UI settings.
    • Choose a Provider type: select OAuth2/OpenID Connect as the provider type.
    • Configure the Provider: provide a name (or accept the auto-provided name), the authorization flow to use for this provider, and the following required configurations.
      • Note the Client ID and Client Secret values because they will be required later.
      • Add a Redirect URI of type Strict Authorization as https://mailcow.company.
      • Select any available signing key.
      • Under Advanced protocol settings:
        • Remove the authentik default OAuth Mapping: OpenID 'email' scope from Selected Scopes.
        • Add the custom email scope mapping to Selected Scopes.
        • Add the mailcow_template scope mapping to Selected Scopes.
    • Configure Bindings (optional): you can create a binding (policy, group, or user) to manage the listing and access to applications on a user's Application Dashboard page.

  3. Click Submit to save the new application and provider.

mailcow configuration​

To configure mailcow with authentik, log in as an administrator and navigate to System > Configuration. Then, go to Access > Identity Provider, select Generic-OIDC as the identity provider, and enter the following information in the form:

  • Authorization endpoint: https://authentik.company/application/o/authorize/
  • Token endpoint: https://authentik.company/application/o/token/
  • User info endpoint: https://authentik.company/application/o/userinfo/
  • Client ID: <Client ID from authentik>
  • Client Secret: <Client Secret from authentik>
  • Redirect URL: https://mailcow.company
  • Attribute Mapping:
    • Attribute: default
    • Template: Select the mailbox template that should be used for users with mailcow_template: default.

To let existing mailboxes log in with authentik, navigate to E-Mail > Configuration > Mailboxes, edit the mailbox, set Identity Provider to Generic-OIDC, and save the changes.

For users who do not already have mailboxes, mailcow can create a mailbox when the user signs in. Enable Auto-create users on login and configure either Default Template or an Attribute Mapping that matches the mailcow_template claim returned by authentik.

Users who log in with Generic-OIDC can create passwords for external mail clients from the mailcow UI by opening Mailbox Settings and using the App Passwords tab.

Configuration verification​

To confirm that authentik is properly configured with mailcow, open mailcow and log in via authentik.

Resources​