A $25 Million Company Just Made It Easier for AI Platforms to Work With Many Programming Languages

A startup called Stainless has raised $25 million in funding to solve a technical problem that's become increasingly common: how do large software platforms efficiently support many different programming languages at once?

The company, based in New York and founded in early 2022, works with big names like OpenAI, Anthropic, and Cloudflare. Its customers span AI platforms, financial services companies, and developer tools.

Why This Problem Matters

When a software company releases an application programming interface—think of it as a digital bridge that lets other software talk to their service—they need to provide ways for programmers to use it. A programmer writing in Python needs different instructions than one writing in Java or JavaScript.

Traditionally, large companies hire teams of engineers to hand-build these instructions, called SDKs or "software development kits," for each programming language they support. It's repetitive work. When the company updates its API, all those language-specific versions need updating too. The more languages you support, the more engineering time this takes.

Stainless automates this process. Instead of humans writing each version separately, the company's software reads the API specifications and generates the code automatically—for Python, JavaScript, Go, and other languages. The result is consistency: all the language versions work the same way and get updated at the same time.

Who Uses This

Stainless's customers paint a clear picture of where this tool matters most. In the AI world, it generates code for OpenAI's ChatGPT API, Anthropic's Claude, Runway's creative AI tools, and Meta's Llama models. In financial services, it works with billing companies and payment processors. It also works with infrastructure platforms like Cloudflare and Mux.

These companies share something in common: they build services that other programmers integrate into their own applications. The quality and ease of those integrations directly affect whether developers choose to use their service.

Why Now?

The timing makes sense for a few reasons. The recent explosion of AI services means developers are now juggling multiple AI APIs in their code at once. They need reliable, consistent tools to work with all of them. At the same time, financial technology has become increasingly modular—more companies are building specialized pieces rather than monolithic platforms. Both trends mean more APIs, and therefore more need for reliable, automatically generated client libraries.

There's also a practical point worth noting: the market for startup funding has become more selective. Most investor money is flowing toward companies with clear business models and immediate market demand. Stainless securing $25 million in a cautious funding environment suggests investors see real momentum here.

What This Enables

Over my three decades covering technology, I've watched companies solve similar problems before—think of how database companies automated schema management, or how cloud providers automated server provisioning. What's happening here is similar: engineers get freed up to focus on what matters more, while automation handles the repetitive parts.

The broader implication is about developer experience. When a software platform makes it easy to integrate with their service—through well-maintained, consistent client libraries in multiple languages—more developers actually use it. That drives adoption. For companies like OpenAI or Cloudflare, that's a business advantage.

The $25 million Stainless raised positions the company to expand its technical capabilities and add more customers as companies increasingly build their business around APIs. For developers and the platforms they use, this kind of infrastructure automation tends to make things quieter, easier, and less error-prone—exactly what works best.