Is Nikita Bier Joining OpenAI? Codex Head Welcomes Former Exec After X Resignation

Nikita Bier joining OpenAI became a brief, viral rumor on August 6, just hours after he confirmed he was leaving X. OpenAI Codex lead Andrew Ambrosino triggered the chatter, then defused it within the same breath.

Ambrosino posted that Bier had joined the Codex team, a nod to Codex, OpenAI’s AI coding assistant. He added a follow-up line an hour later that read simply, ” This is a joke.”

Why Rumors Spread So Fast

Bier had just confirmed he was stepping down as head of product at X after roughly one year in the role. That timing made Ambrosino’s post read, briefly, like a real hire announcement.

this is a joke

— Andrew Ambrosino (@ajambrosino) August 6, 2026

Bier built his public profile on earlier viral consumer apps before Elon Musk recruited him to lead X’s product team in July 2025. He spent that year on aggressive recruiting himself, poaching engineers from Meta with pay and perks pitches.

Consequently, a jump to a rival AI lab sounded plausible to readers who scrolled past the joke’s punchline. Ambrosino genuinely leads Codex, so the post carried real authority on its own.

Moreover, Codex’s usage has grown sixfold since February to more than 5 million weekly users, by Ambrosino’s own account. That scale helps explain why one line from him traveled so fast.

In turn, Bier’s farewell post also named three successors. Designer Benji Taylor, Mridul Singhai, and Jonah Katz now split his old job across design, product, and mobile engineering.

🥰

— Elon Musk (@elonmusk) August 6, 2026

That handoff, covered in an earlier report on his exit, added to the sense that something at X was truly shifting.

Musk and OpenAI’s Rivalry Gave the Joke Extra Bite

Musk had already thanked Bier for his work before the joke even circulated widely.

Thanks for helping make this platform much better! You will be missed.

Musk wrote that in a reply to Bier’s farewell post the same day. However, the joke landed with extra weight because Musk and OpenAI keep sparring in public.

A jury dismissed Musk’s own lawsuit against OpenAI and Sam Altman in May, ruling he filed his claims too late. Musk has since kept criticizing the company anyway, most recently reacting to Apple’s OpenAI lawsuit over trade secrets this month.

That ongoing back-and-forth gave Ambrosino’s joke about hiring a Musk lieutenant extra bite. Musk has also pushed his own Grok models as direct rivals to OpenAI’s software throughout the year.

Beyond the viral humor, one thing is clear: Bier is not switching sides but will remain with X as an advisor. Following his resignation from day-to-day operations, he is simply taking a brief breather. Whether he will eventually transition into the AI sector remains to be seen.