A company that provides SDKs to OpenAI and Google, Anthropic, is set to be acquired for twice its valuation.

According to Datamation Beating monitoring, Anthropic is in advanced negotiations to acquire developer tool company Stainless, with a price tag of at least $3 billion. What Stainless does is use AI to automatically convert complex APIs into SDKs (Software Development Kits), making it easier for developers and AI agents to invoke models. Its customer list is quite interesting: OpenAI, Google, and Anthropic itself are all users.

This means that if the deal is reached, Anthropic will directly control a key channel for competitors to access the model. OpenAI previously maintained its own SDK, with its senior engineer stating that the maintenance costs were high and required a large amount of resources, and later switched to Stainless. Currently available alternative solutions include Speakeasy, LibLab, and the open-source OpenAPI Generator, but Stainless holds the most prominent market position.

Stainless, founded 4 years ago, is headquartered in New York, with a team of about 80 people and total funding of $35 million. Investors include a16z, Sequoia, and Felicis. In December 2024, its last funding round valued the company at $1.5 billion, making this acquisition price a double premium. Anthropic was valued at $350 billion in February this year and may use a portion of its stock to pay the consideration. The negotiation has not been finalized, and the terms are still subject to change.

In addition to serving the three major model vendors, Stainless also provides SDK tools for non-model companies such as Cloudflare and Cerebras, and has developed complementary software for Anthropic's MCP (Model Context Protocol) released in November 2024. This acquisition is also Anthropic's fourth in six months: after acquiring the JavaScript runtime Bun in December last year, it subsequently acquired the computer operator Vercept and the AI biotech company Coefficient Bio.