AI startups like OpenAI, Anthropic, and Together AI share a common thread besides focusing on generative AI – they all use Stainless, a platform created by ex-Stripe staffer Alex Rattray, to generate SDKs for their APIs.
Alex Rattray, with a background in economics from the University of Pennsylvania, has a history of building innovative projects, starting from an underground newspaper in high school to a bike-share program in college. His programming skills, acquired during his time at UPenn, landed him a job at Stripe, where he played a key role in revamping API documentation and launching Stripe’s API client SDK system.
While at Stripe, Rattray noticed a gap in the market for companies to efficiently build SDKs for their APIs at scale. This led him to create Stainless, a platform that takes an API spec and generates SDKs in various programming languages like Python, TypeScript, Kotlin, Go, and Java. Stainless also provides options for versioning, publishing changelogs, and AI-driven updates.
Stainless has attracted notable clients like OpenAI, Anthropic, and Together AI, offering them a polished solution with the help of generative AI. With dozens of paying clients in its beta phase, Stainless has proven its value by simplifying the SDK generation process and improving developer experience.
Rattray emphasized the importance of great SDKs for driving faster integration and broader feature adoption, highlighting Stainless’s role in enhancing API-driven platforms. While publishing a single SDK with Stainless is free, companies can opt for the enterprise tier with additional services and functionality, priced between $250 per month and $30,000 per year.
Stainless, self-funded from day one, is on track to profitability this year with annual recurring revenue close to $1 million. Despite this success, Rattray chose to secure outside investments to expand Stainless’s product offerings. Recently, Stainless closed a $3.5 million seed round with backing from Sequoia and The General Partnership.
Anthony Kline, partner at The General Partnership, praised Stainless for elevating the developer experience and positioning itself as a leading platform for seamless API interactions. With a growing team based in New York, Rattray plans to expand headcount to 15-20 by the end of the year, reflecting the company’s rapid growth and promising trajectory.
