Central admin management of mailbox access and signatures in Nextcloud Mail

[Bytrider]

Is your feature request related to a problem?

Nextcloud Mail currently lacks functionality for centralized administration of mailbox access and email signatures.

In organizational environments (e.g. associations, SMEs, care facilities, schools), email communication is often based on:

• shared mailboxes (e.g. info@, support@, board@)
• role-based access instead of individual ownership
• standardized, CI-compliant email signatures

At the moment:

• mailbox access must be configured manually per user/client
• signatures are managed individually by users
• administrators have no way to enforce or centrally maintain signatures

This leads to inconsistent configuration, higher administrative overhead, and non-uniform external communication.

Describe the solution you'd like

1. Admin-managed mailbox access (Nextcloud Mail)
Extend Nextcloud Mail with an admin-level mailbox management interface, allowing administrators to:

• centrally define mailboxes (email addresses)

• assign users to mailboxes

• define access levels per user:

  • read-only
  • send
  • full access

• manage visibility and sending rights independently of the user’s personal mail setup

This should integrate with the existing Nextcloud Mail account handling and permissions model.

2. Centralized signature management by administrators
Provide an option for administrators to manage email signatures:

• per user
• per mailbox
• or as a global default

Features:

• edit signatures in the Admin Settings
• optionally lock signatures (read-only for users)
• define whether users are allowed to override admin-defined signatures

This ensures consistent communication and reduces user-side misconfiguration.

3. HTML signature templates with variables
Add support for HTML-based signature templates, including:

• uploading or defining signatures as .html templates
• reusable templates
• variable placeholders that are replaced dynamically, e.g.:

Kind regards
{{displayName}}
{{jobTitle}}
{{organization}}
Email: {{email}}
Phone: {{phone}}

Possible variables:

• username
• display name
• email address
• organization / department
• phone number
• role or group

This allows administrators to enforce corporate identity–compliant signatures while still using user-specific data.

Describe alternatives you've considered

No response

Additional context

Benefits

• Centralized administration for Nextcloud Mail

• Consistent and professional email signatures

• Reduced setup and support effort

• Particularly useful for:

  • organizations with shared mailboxes
  • teams with role-based communication
  • environments with compliance or CI requirements

Optional enhancements / future ideas

• Signature preview in Admin Settings
• Multiple templates selectable per mailbox
• Signature depending on sender address
• API support for automated provisioning

Additional context

This feature would significantly improve Nextcloud Mail’s suitability for organizational and multi-user deployments, aligning it more closely with real-world administrative workflows.