Can I use Firewall AI together with another VPN service?

Currently, no. At this time, you cannot use Firewall AI on Android at the same time as another active VPN service. In the official FAQ, Protectstar answers this directly with “No, currently it is not possible.”

The technical reason lies in Android itself: according to Android Developers, there can only be one active VPN service per user or profile, and only one app can be the currently prepared VPN app. When a new VPN service starts, any existing active service is ended. That is exactly why Firewall AI competes with classic VPN apps for the same system mechanism.

In practice, this means that if you are already using a service such as NordVPN, Mullvad, or IVPN, you currently have to choose one of the two solutions on Android. Protectstar explicitly points out in the Firewall FAQ that Firewall AI therefore cannot run in parallel with other VPN apps.

If you are mainly looking for DNS features, one additional point matters: Protectstar explains in another FAQ that many DNS changer functions are already built into Firewall AI, and that the firewall can also be configured with a different DNS server. In some cases, that can be a practical alternative if you cannot use a second VPN service at the same time.