Nikita Bier has stepped down as head of product at X, the social media platform formerly known as Twitter. His resignation took effect August 6, 2026, after roughly a year in the role. Bier will stay on as an advisor.
Why Bier left
Bier announced his departure in a post on X. Elon Musk replied publicly, thanking him for his work. The company did not give a reason for the change. Bier's responsibilities will now be split among three people: designer Benji Taylor, product lead Mridul Singhai, and mobile engineering lead Jonah Katz. The move suggests X is reorganizing its product team rather than replacing Bier with a single executive.
The joke that wasn't
Hours after Bier's announcement, Andrew Ambrosino, the lead of OpenAI's Codex team, posted that Bier had joined Codex. Ambrosino walked it back within an hour, calling it a joke. The brief confusion played into the long-running rivalry between Musk and OpenAI. Musk has spent 2026 promoting his own Grok AI models as direct competitors to OpenAI's software. In May, a jury dismissed Musk's lawsuit against OpenAI and CEO Sam Altman. Musk continues to criticize the company publicly.
With Bier moving to an advisory role, the three new leads will handle design, product strategy, and mobile engineering. It's not clear how much authority each will have or whether X plans to hire a new head of product later. The company has been pushing new features, including payments and AI tools, but has not announced a replacement for Bier's day-to-day role.
Codex growth and rivalry
Ambrosino also revealed that Codex usage has grown sixfold since February 2026, now serving more than 5 million weekly users. That growth comes as Musk continues to position Grok as an alternative. The two companies are competing for developers and consumers in the AI space. Bier's departure from X does not directly affect that rivalry, but the timing of the fake hiring post added a layer of snark.
Bier's next move is unknown. He remains an advisor to X, but his full-time focus is unclear. Musk has not commented on whether he plans to hire a permanent product chief.
