FindBetaTesters…

Beta testers for iOS apps

iOS betas need TestFlight or a clear install path. These communities tolerate app promos when you lead with what you want feedback on — not a launch announcement. Check each place's rules before posting your link.

FAQ

Do I need TestFlight before recruiting?
You need a build testers can install. TestFlight is the usual route; say in your post which iOS versions you support.
How many iOS testers should I aim for?
Start with 10–30 engaged testers who match your target user. Quality beats a large silent install base.