New Delhi, July 21 -- SAN FRANCISCO - For a long time, clicking a link to an X post from another app on Android was an exercise in frustration. The X app would open, spin briefly, and then fail. The post the user came to see simply would not load. It was not a minor glitch. It was a fundamental symptom of a codebase that had accumulated years of technical debt, stretched far beyond what it could reliably sustain.

X launched a rebuilt Android app on Sunday, replacing that creaking foundation with one written entirely in Kotlin and Jetpack Compose. Nikita Bier, the company's head of product, called it "one of the largest engineering projects" in X's history. The app, which the company spent nearly a year rebuilding from scratch, is now liv...