Running a VPN server on iOS is against AppStore's Guidelines
developer.apple.com
developer.apple.com
Surely iOS allows some kind of soft VPN API that this developer can use?
The user is probably looking for something similar, as ios only supports ipsec/ikev2/l2tp natively. If you want to use wireguard or openvpn you have to get creative.
Hm? There's been an official Wireguard app on the App Store for years[1]. I've been a happy user of it since day 1.
Setting up a double VPN client/server system seems unnecessarily complicated to me. I wonder what drove Mullvad to this solution.
https://github.com/WireGuard/wireguard-apple/blob/13b720442d...
And you're right that iOS does have an API for this: the NetworkExtension framework explicitly allows for custom VPN solutions[1].
[1]: https://developer.apple.com/documentation/networkextension