Fluid UI vs ProtoPie

Fluid UI is a web-based tool for making, previewing, sharing, and exporting mobile app mockups. It supports interactive web and mobile prototypes with taps, swipes, clicks, and other gestures, plus page effects such as fades, flips, and pop-ins. The built-in library contains more than 2,000 components spanning Material Design, iOS, Windows, and wireframe styles. Teams can collaborate on cloud-saved projects in real time. Reviewer mode supports shared click-throughs, chat, annotations, and comments, and the service also supports remote user testing sessions. Fluid UI runs in Firefox and Chrome, offers an installable desktop client, and has Android and iOS preview apps. There is a free plan and a free trial. Paid plans include Solo at $8.25 a month for five active projects, one user license, and unlimited reviewers; Pro is $19.08 a month, and Team is $41.58 a month.

ProtoPie is a high-fidelity platform for creating and testing interactive digital prototypes. Studio for macOS and Windows supports logic, variables, formulas, multi-touch gestures, text input, media playback, voice, camera access, and device sensors such as gyroscopes and compasses. Plugins import designs from Figma, Sketch, and Adobe XD. Prototypes can connect phones, tablets, TVs, and wearables, with interactions synchronized across devices. The product ecosystem includes Studio, Player for mobile devices, Cloud for sharing, and Connect for connected experiences. Player is available for iOS, iPadOS, Android, and HarmonyOS. The Free plan includes two prototypes saved in Cloud, up to eight scenes per prototype, and 50MB of Cloud storage. ProtoPie lists Basic at $25 a month billed yearly, and Pro at $47 a month billed yearly. Free-plan limitations include no local file saving, share links, Handoff, or Team Libraries. Prototypes export only as.pie files, not PDF, JPEG, or HTML code.