Highlights:
- The Stainless SDK generator has helped thousands of developers by providing SDKs with products, making it easier to build applications.
- Stainless’ AI algorithms generate an initial SDK configuration, which developers can fine-tune, avoiding issues with inconsistent or outdated libraries.
A company leveraging artificial intelligence to enable rapid creation of software development kits for applications and services, Stainless Software Inc., has secured USD 25 million in early-stage funding.
The recent Series A funding round, led by Andreessen Horowitz, saw participation from existing investors like Sequoia and The General Partnership. It also included contributions from prior backers such as Felicis, Zapier, MongoDB Ventures, and angel investors, including former Stripe Inc. COO Claire Johnson and Datadog Inc. President Amit Agarwal.
The startup has created a tool that employs an AI-powered compiler to automatically generate software development kits (SDKs) from application programming interfaces with minimal developer input.
The Stainless SDK generator has already demonstrated its value to thousands of developers, who rely on technology companies to supply SDKs alongside their products to simplify the process of building applications that utilize those products. However, developers often face disappointment, as many companies only offer an API—a protocol enabling software components to communicate with one another—rather than a full SDK.
While APIs have become the cornerstone of nearly all modern applications, SDKs remain far less prevalent. This is primarily because developing SDKs is an exceptionally complex task, and many companies lack the required skills and expertise to tackle it effectively.
In a blog post, Stainless founder and CEO Alex Rattray explained that an SDK essentially serves as a blueprint for developers to build applications. Without an SDK, API users must sift through extensive documentation and construct everything from the ground up. Therefore, there’s a clear need for a solution that makes it easy for every company to offer an SDK alongside their APIs.
In an era where AI can already automate the creation of entire applications and codebases, it’s logical for AI to handle the generation of usable SDKs as well—and that’s precisely what Stainless aims to do. The Stainless SDK generator analyzes an API’s specifications and produces an SDK compatible with multiple programming languages, such as Python, Kotlin, TypeScript, and Go. As the API evolves, Stainless ensures its SDKs stay up-to-date by incorporating those changes and adapting accordingly.
Stainless’ AI algorithms kick off the process by creating an initial configuration for the SDK, which developers can then adjust and refine as needed. This approach helps prevent issues with inconsistent or outdated libraries.
“Using Stainless, companies can build a world-class API DX without dedicating full-time engineers to SDK maintenance. Their SDKs are consistent across languages, up-to-date and easy for developers to use, even with rapidly changing APIs,” Rattray said.
Stainless isn’t a completely novel concept, as other startups like LibLab Inc. and Speakeasy Inc. also provide SDK generators for APIs, along with open-source alternatives like the OpenAPI Generator project. However, Rattray argues that Stainless stands out from its competitors thanks to its compiler, which he claims produces significantly more “polished” code.
The proof is in the results, as many top AI companies have chosen to use Stainless over other alternatives. The startup claims its customers include major names such as OpenAI, Anthropic PBC, Meta Platforms Inc., Runway AI Inc., Cerebras Systems Inc., and Cloudflare Inc.
Rattray asserts that Stainless has hundreds of paying customers and that “millions of AI developers” download its SDKs every week.
The company offers its SDK generator in multiple tiers, including a free version that lets users publish a single SDK. However, to generate and publish multiple SDKs in various programming languages, companies must pay anywhere from USD 250 per month to USD 30,000 per year.
Stainless’ business model seems to be successful, as Rattray told in an interview that the company has generated approximately USD one million in annual recurring revenue, bringing it close to profitability.
Rattray is optimistic about his company’s future, anticipating that APIs will play an even more critical role as AI adoption continues to grow. After all, APIs are vital components of the data pipelines that power every AI application.
He said, “AI agents will rely on (and will favor) robust, well-designed APIs to interact with various services and data sources, enabling them to execute complex workflows.”