M66B/NetGuard

On GrapheneOS there is a Network permission to forbid access completely. Or you can also use something like NetGuard[1], to have more flexible controls. [1]: https://github.com/M66B/NetGuard

…ob/a-couple-updates/service/src/main/kotlin/dev/clombardo/dnsnet/service/vpn/DnsNetVpnService.kt They both do the same thing. There are local device-only resolver apps like https://rethinkdns.com/ https://github.com/m66b/netguard Another famous one is DNS66 but it's sadly unmaintained. Avoid apps with the word "ad" in their name, they are usually semi commercial and can't be trusted. Do note all of these methods can be overridden on the app level e.g. a lot of browsers come bundled with first party VPNs or use their own built-in resolvers. If you want something more reliable, Firefox on Android with the UBlock Origin and Sponsorblock extensions is still the gold standard. Though do not…

If you're feeling skeptical and just want to be sure, you can use this NetGuard https://github.com/M66B/NetGuard to block internet access for any app.

Pro tip: use the fdroid version as it allows you to set a host file to also filter ads, etc. https://github.com/M66B/NetGuard/blob/master/ADBLOCKING.md