Anthropic is in advanced talks to acquire Stainless for more than $300 million, according to a report by The Information on Wednesday.
The deal has not yet been finalised, and the terms could still change. Part of the payment may also be made using Anthropic shares, the report added.
Founded in early 2022 by Alex Rattray, Stainless builds software that helps developers access and use artificial intelligence models more easily. Its customers include Anthropic, OpenAI and Google.
If the deal goes through, Anthropic would take ownership of a major tool that developers use to access AI models from companies such as OpenAI and Google.
Demand for Stainless’ tools has reportedly grown alongside the rise of AI agents such as Claude Code and OpenCode.
OpenAI had previously developed its own software development kit, but later adopted Stainless’ tools because maintaining the system internally became difficult and resource-heavy. Stainless has also built software linked to Model Context Protocol (MCP), a framework launched by Anthropic in November 2024.
This comes as Bloomberg reported on Wednesday that Anthropic is in early discussions with investors to raise at least $30 billion in fresh funding.
The report said the round could value the company at more than $900 billion, excluding the investment itself. That would be more than double Anthropic’s reported $380 billion valuation from its February funding round.
Bloomberg added that discussions are ongoing, and no formal agreement or term sheet has yet been signed.
Founded in 2021 by former OpenAI employees, Anthropic has emerged as one of the leading companies in the AI industry. It has developed a range of AI products focused on tasks such as coding and cybersecurity.
