- Windows: Simplewall (uses native WPF for filtering), Portmaster (interactive firewall, uses custom kernel extension).
- macOS: LuLu or Little Snitch (they all use a native filtering API, which unfortunately is not perfect: https://lapcatsoftware.com/articles/2023/6/3.html).
- Linux: OpenSnitch, denying network permission to Flatpak apps.
- Android: Rethink, NetGuard; GrapheneOS has app network permission natively.
iOS is the only OS where no application firewall is available, although if you don't use Wi-Fi, you can block apps from using cellular data.
- Windows: Simplewall (uses native WPF for filtering), Portmaster (interactive firewall, uses custom kernel extension).
- macOS: LuLu or Little Snitch (they all use a native filtering API, which unfortunately is not perfect: https://lapcatsoftware.com/articles/2023/6/3.html).
- Linux: OpenSnitch, denying network permission to Flatpak apps.
- Android: Rethink, NetGuard; GrapheneOS has app network permission natively.
iOS is the only OS where no application firewall is available, although if you don't use Wi-Fi, you can block apps from using cellular data.