In the realm of software development, developers typically expect technology providers to furnish Software Development Kits (SDKs) to simplify the process of building applications based on their products. However, many suppliers offer only Application Programming Interfaces (APIs), which are protocols that facilitate communication between different software components.

Addressing this issue, Alex Rattray, the founder of Stainless, introduced a solution. Stainless utilizes a compiler to automatically generate SDKs from APIs, enabling nearly instantaneous implementation. Rattray notes that without SDKs, API users must read documentation and construct everything themselves, while providers struggle to create SDKs for APIs on a large scale.

Stainless takes API specifications as input and produces SDKs covering programming languages such as Python, TypeScript, Kotlin, and Go. When the API is updated, the platform pushes the corresponding changes, offering options for version control and publishing change logs.

Traditionally, providers might require internal developers to write libraries in multiple languages to connect to APIs. In contrast, Stainless employs artificial intelligence to generate the initial configurations, which teams can then fine-tune to accommodate specific APIs. This approach helps prevent inconsistencies or outdated issues in library files and accelerates the speed of upgrades and integration times.

Rattray believes that in the future, every business with a website will witness APIs transitioning from advanced user features to primary interfaces accessible to all users. Companies lacking high-quality APIs will seem as outdated as restaurants without websites.

While major technology companies like OpenAI, Anthropic, and Meta are currently utilizing the Stainless platform, it has amassed weekly download counts in the tens of millions. The primary customers opt for enterprise-level services that include additional customization and AI features. Pricing for multiple SDKs across various programming languages ranges from $250 per month to $30,000 per year.

Stainless has raised approximately $35 million in funding, with the latest round being a $25 million Series A led by a16z, alongside investments from Sequoia, The General Partnership, Felicis, Zapier, and MongoDB. The funds will be used to expand the team based in New York, which currently has around 20 members.