The move was announced on X by OpenAI’s product leader, Thibault (Tibo) Sottiaux, who leads core products like Codex and ChatGPT at the AI lab. He said that the Pro plan puts the most strain on its systems, which is why sign-ups for this service tier are now being disabled.

“We wanted to take the smallest step that allows us to continue giving the broadest access possible,” Sottiaux wrote. He added that the company’s other plans, including the API and lower-cost Go and Plus plans, remain available.

The company warned on Wednesday that such a change might come. At the time, Sottiaux wrote, “Demand for Astra is really unprecedented. We’re pulling all the levers possible to sustain the demand, but I’ve not seen anything like it until now and we went through very steep growth before. Priority will always be to keep excellent service for existing users, but we might have to pause new Pro subscriptions for a bit if this continues.”

OpenAI hasn’t said how long sign-ups to the Pro tier may be disabled, or how many people are signing up daily, to give an idea of the scale of the demand.

The company raised usage limits for Codex users as recently as last month, suggesting the strain is a recent phenomenon.

Launched on September 3, Astra has been rolling out across OpenAI’s plans, including Pro, Plus, Enterprise, and Business accounts, in addition to its AI. The model promises a major leap forward in areas like AI reasoning, coding, and computer use — all areas of steep competition. OpenAI even heralded Astra as the beginning of the “AGI era,” and a generational leap, stoking demand even more.