Verifium
The ultimate iOS security & privacy auditor.
Why Verifium
Your phone knows where you live, who you talk to, what you search for. Most people have no idea if their device is actually secure.
Verifium is a checklist. Current version has 23 checks drawn from hardening best practices (ANSSI, CISA and Apple's own guidelines).
Free and open-source. The app makes one network request (checking your iOS version). Everything else runs locally. No data collected, ever (Privacy Notice).
Screenshots
Multiple checks
Device, network, apps, privacy, data protection
Walk-through
Each check tells you what to do and where to find it
Sourced
Every recommendation links back to its original publication
Open-source
Read the code and fork it if you want to (GPL-3.0).