OpenAI on Thursday announced it is acquiring Astral, a small startup known for building popular open-source tools for software developers.

Astral’s team will join OpenAI to support the development of its AI coding assistant, Codex.

The companies did not disclose the financial terms of the deal.

“Through it all, though, our goal remains the same: to make programming more productive. To build tools that radically change what it feels like to build software,” Astral’s founder and CEO Charlie Marsh wrote in a blog post.

AI coding assistants have surged in popularity over the past year, with OpenAI competing for developers against rivals such as Anthropic and Cursor, both of which offer their own widely used developer-focused tools.

OpenAI said on Thursday that Codex now has more than 2 million weekly active users, and has recorded a threefold increase in user growth since the beginning of the year.

OpenAI’s acquisition of Astral has yet to be completed and remains subject to standard closing conditions, including regulatory approval.