OpenAI has entered into a definitive agreement to acquire Neptune, a company that provides tools for monitoring and debugging machine learning models.

The acquisition, which remains subject to closing conditions, will see Neptune join OpenAI and continue supporting AI researchers with its platform.

Financial terms of the deal have not been officially announced.

However, The Information, citing sources familiar with the matter, reported that OpenAI would pay under $400m in stock as consideration for the deal.

When contacted, OpenAI did not immediately respond to a Reuters request seeking confirmation of the transaction’s value.

Neptune CEO/CTO and founder Piotr Niedźwiedź said: “OpenAI research converts compute into understanding. At the interface of compute and understanding are metrics. Neptune is a metrics dashboard company.

“We’ve worked closely with OpenAI to create the metrics dashboard that helps teams building foundation models. With this transaction, we’ll be able to work even more closely together and innovate on tools at a whole new level.”

Neptune began as an internal tool at Deepsense before spinning off as an independent startup in 2018. Since its founding in 2017, Neptune has focused on solutions for teams training machine learning models.

According to its website, the company has received more than $18m in funding to date.

OpenAI already uses Neptune’s tracker to monitor and debug the training of its GPT large language models.

Other companies using Neptune’s products include Samsung, HP, and Roche.

OpenAI chief scientist Jakub Pachocki said: “Neptune has built a fast, precise system that allows researchers to analyse complex training workflows.

“We plan to iterate with them to integrate their tools deep into our training stack to expand our visibility into how models learn.”

OpenAI, led by Sam Altman, was valued at $500bn in October 2025, after a deal allowed current and former employees to sell approximately $6.6bn in shares.