Anthropic is in talks to acquire developer tools startup Stainless for at least $300 million, The Information reported on May 12, citing a person familiar with the matter.

Stainless, founded 4 years ago, has provided software that uses AI to automatically generate software development kits (SDKs) that help developers more easily access AI model APIs for AI model companies including Anthropic, OpenAI and Google.

Demand for Stainless tools is also rising as AI agents such as Claude Code and OpenClo spread.

If Anthropic acquires Stainless, it would own a key channel for access to OpenAI and Google models. OpenAI previously developed its own SDK, but adopted Stainless because maintenance was difficult and resource burdens were high. Stainless also built dedicated software that links with MCP (Model Context Protocol), which Anthropic launched in November 2024.

The talks have not been finalised and terms could change. Anthropic may pay part of the acquisition price in its own shares, the source said.

Anthropic has recently been aggressive on mergers and acquisitions over the past 6 months. After its first acquisition of developer tools startup Bun in December last year, it acquired computer use startup Vercept and AI biotech startup Coefficient Bio in succession. Anthropic is expected to continue pursuing acquisitions in several areas including financial services, healthcare and cybersecurity.