Third-party App Connector

All Apps Under One Roof

Provide your users with instant access to a range of popular webmail and communication apps.

WebMail Lite

The App Connector is available for preview and testing in our hosted online demo.

Online Demo

Available on iOS and Android

All apps that are supported by the App Connector are also accessible to your users within your own Android and iOS apps.

Find out more about making it your own.

App Connector

9.95 /mo


Each user can seamlessly switch between different email accounts and apps, even if the email accounts themselves reside on separate servers. This provides users with great flexibility in multi-tasking across multiple accounts and apps from a single UI.

Fully Isolated

Every domain has its own app, database, and runs in a fully isolated environment, under the account's permissions. Aside from improving security in large environments, full isolation also means third-party apps adherence to the account's disk and database quotas.

Optimized and Updated

The environment in which the app is running is optimized to satisfy its individual needs. All app updates are handled automatically by CrossBox. For caching, Roundcube and Nextcloud are pre-configured to take advantage of Redis cache.


When used with the CrossBox Cluster, each app runs on the resolved slave server and under the account's permissions, with app and account routing done automatically by the master server.

Module Mapping

Using the module mapping interface located in Settings -> Apps, each user can freely map modules to dedicated apps. For example, a user can choose CrossBox for email but Nextcloud or Horde for the calendar. Users can also choose to disable certain modules entirely.