For privacy protection and performance reasons, some extensions that use certain application program interfaces (APIs) cannot be installed in the Cliqz Browser. The following extensions and APIs are blocked by Cliqz:

1. Language packs
2. Themes
3. Extensions that capture the new tab or start page
4. Extensions that change the suggestions displayed in the search drop-down (Omnibox API)
5. Extensions that exchange messages with a native application installed on the user’s computer (Native Messaging)

If you are trying to install an extension blocked by Cliqz, you will receive the following error message: