Pttrns is a library of mobile UI patterns and full app screenshots, organized by pattern type (onboarding, empty states, permissions) and by individual app — similar in spirit to Mobbin but mobile-only.
Because it's organized by pattern as well as by app, it's easy to pull ten different apps' solutions to the same UI problem side by side, which is faster than browsing app-by-app.
Best for mobile app designers specifically — there's no web app coverage here, so it's a narrower tool than some of the broader multi-platform screenshot libraries.
The site recently dropped its paywall and went fully free, which is good news, but it also means the library's update pace and long-term maintenance are less certain than when it ran as a paid product.
