4 Pics 1 Word

Reaching new users at Lotum with Flutter

Success metrics




reduction in engagement


Eight years in, Lotum’s flagship game 4 Pics 1 Word was in need of a refresh. After more than 450 million downloads worldwide, user numbers were finally starting to show a slight decline. So the team at Lotum decided to rewrite the game for every platform and give 4 Pics 1 Word a tuneup.

Why Flutter?

For many years, Lotum maintained separate code bases for iOS and Android. But as the team grew, it seemed that half their development time went into troubleshooting cross-platform functionality. Plus, different features exposed different problems on either platform, so development speed was not always aligned.

When Lotum decided to expand into web-based games, they took the opportunity to look for a cross-platform development solution. Eventually, the choice came down to either Flutter or a web-based solution involving Vue.js and a custom bridge to native code. Initially, the team decided to try the web-based approach, but they were soon confronted by a lot of limitations and were constantly looking for workarounds. Also, because 4 Pics 1 Word is often downloaded and played offline on low-end devices, the web approach wasn’t a great fit. So after three months, the team switched course and started over with Flutter.

Their Solution

Lotum used Flutter to completely rewrite 4 Pics 1 Word as a cross-platform app. Whereas other cross-platform frameworks either try to emulate native components or translate cross-platform code into their native counterparts, Flutter uses its own rendering engine, Skia, to offer a consistent game layout, look, and feel. This was important to the team, as it would help them achieve the feature parity they felt they had previously lacked.

“With the introduction of Flutter, the morale in the team skyrocketed.”

- Dennis Becker, Head of Development, Lotum


Based on their previous version launches, Lotum expected to see a temporary drop in daily active users and ad revenue due to instability issues. But when they released the new version of 4 Pics 1 Word, not only did their user engagement numbers remain constant, their vitals actually went up. In fact, Lotum reports that the Flutter version is even more stable than the native counterpart was, with a steady 99.9% crash-free rate.

And because Lotum uses Google AdMob to centralize their ad partner management, they were excited by the seamless integration between Flutter and Google AdMob — especially because 90% of their revenue comes from ads.

Ultimately, the development team enthusiastically embraced Flutter and plan to continue using it to develop future apps.