Neptune Joins OpenAI: MLOps Consolidation Continues

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OpenAI has acquired Neptune.ai, the Polish-founded training observability platform, for less than $400 million in stock. The deal, announced December 3, 2025, marks OpenAI’s first acquisition in Eastern Europe and continues the rapid consolidation of the MLOps market.

What is Neptune?

Neptune.ai is a training observability platform for foundation models. Founded in 2017 as a spin-off from Polish AI firm deepsense.ai, the company built tools that help researchers track, monitor, and analyze complex ML training workflows. OpenAI has been a Neptune customer for over a year.

Jakub Pachocki, OpenAI’s Chief Scientist:

“Neptune has built a fast, precise system that allows researchers to analyze 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.”

The roughly 60-person team, now headquartered in Palo Alto with offices in Warsaw, will join OpenAI.

The End of the Platform

For existing customers, this is an acqui-shutdown:

• March 4, 2026 at 10 AM PST: The hosted app and API will be permanently turned off
• All remaining hosted data will be “securely and irreversibly deleted”
• OpenAI will keep the technology for internal use only

The Investor Angle: Andreas Goeldi and btov

Andreas Goeldi, Partner at b2venture (formerly btov Partners), led Neptune’s $3 million seed round in 2020. It was btov’s first major investment in Poland.

At the time, Goeldi noted: “Data science is one of the most dynamic markets in IT today and yet still immature in terms of its commonly used toolset.” He served as a board member/observer at Neptune through the exit.

According to an NZZ interview, the acquisition story included a call from Sam Altman himself. Goeldi called the $400M exit “just the beginning for Europe’s tech scene.”

The pivot paid off: In 2023, Neptune completely shifted to its new product—a risky move extensively debated at the board level. With a team of 40 engineers, they built something with clear market differentiation that caught OpenAI’s attention.

MLOps Market Consolidation

This deal follows CoreWeave’s acquisition of Weights & Biases, Neptune’s primary competitor, earlier in 2025. The infrastructure layer for AI development is rapidly consolidating into fewer, larger players.

Other 2025 OpenAI acquisitions:

• io (Jony Ive’s AI devices startup): $6B+ in May
• Statsig (product development): $1.1B in September
• Software Applications Incorporated (interface startup): October

Key Details

Sources:

• We are joining OpenAI - neptune.ai
• OpenAI to acquire Neptune - OpenAI
• OpenAI Agrees to Acquire Neptune - Bloomberg
• Why btov Partners Invested in Neptune - Andreas Goeldi / Medium
• Andreas Goeldi - b2venture