X Android app rebuilt: ground-up rewrite with Kotlin

X has shipped a completely rebuilt Android app, rewriting the client from scratch after nearly a year of development. The new app uses a Kotlin + Jetpack Compose stack to improve loading, scrolling, and notifications, and lays the groundwork for faster feature rollouts on Android.

What happened

X head of product Nikita Bier described the effort as one of the largest engineering projects in the company's history. The rewrite began after the company noted that the Android app had not kept pace with its iOS counterpart. Last August, Bier said X was assembling an Android "dream team." The Android app overhaul arrives after a spike in downloads in October and aims to close the gap between platforms.

X says the new app is "faster, smoother, and more reliable" than the old version. The company also highlighted that the modern foundation will enable faster feature rollouts, including X Money, X Chat standalone apps, a new video editor, react-with-video, cashtags, and custom timelines.

Why AI builders should care

A ground-up rewrite on a modern stack like Kotlin and Jetpack Compose signals that X is prioritizing Android as a first-class platform for new features. For AI builders integrating with X's platform or building complementary tools, this means fewer legacy constraints and faster iteration cycles for Android-native features. The shift can reduce long-term maintenance friction and unlock rapid experimentation for capabilities that depend on the client.

Practical implications

Android dominates global smartphone markets, and X's historically neglected Android experience may have driven users away. The rebuild could broaden adoption and re-engage users in regions where Android is the primary platform. Existing users can update the app through the Google Play Store.

Caveats

X acknowledged rough edges remain, including performance on older Android devices and the absence of Spaces support. Spaces is still under development for Android. Several planned features, including the video editor, react-with-video, cashtags, and custom timelines, are described as "coming soon." The rebuild is a major step forward, but the full feature set will take time to arrive.