In 2025, Stainless made major progress to enable any company to build world-class APIs. We shipped new language support for our SDK generator, a dynamic docs platform, and support for MCP servers derived from your OpenAPI spec. In 2026, every company needs to become an API company, and Stainless is excited to make it happen with you!

Most OpenAPI specs are “mostly right,” but small inconsistencies can break generated SDKs. This post explains when OpenAPI Overlays are enough—and how Stainless Transforms handle harder fixes like schema deduplication, structural renames, and language-aware naming without modifying the upstream spec.

Learn how to maximize the growth potential of your API and minimize your costs at the same time.

A practical guide for API platform teams deciding between hand-written SDKs and generators like Stainless. It breaks down when generation wins (HTTP-heavy, multi-language, spec-driven clients), when custom code is better (logic-first libraries), and why a hybrid approach often delivers the best developer experience.

Introducing the Stainless Docs Platform, now available in early access. Build doc sites for REST APIs, SDKs, and hand-written docs that evolve alongside your API spec. Powered by Astro, so you can customize anything and deploy anywhere.

Handling multiple resource variants in a REST API can be a tricky design challenge, with many considerations and trade-offs to take into account. In this post, we’ll look at an AI image generation API as an example, but the concepts we’re going to discuss are broadly applicable to any API with multiple resource variants.

Stainless preview builds solve the biggest problem blocking API development at scale: engineers can't see how their OpenAPI changes affect SDKs until after they ship. Now you and your team can see exact SDK diffs and test locally without leaving your pull request.

When your job is building SDKs, a dependency manager that defies everyone’s expectations can wreak havoc, and working around third-party behavior can be tricky. Learn how and why we rejected a quick fix and took the time to develop a robust solution that meets our high quality bar.

Despite the hype, Model Context Protocol (MCP) isn’t magic or revolutionary. But, it’s simple, well-timed, and well-executed. At Stainless, we’re betting it’s here to stay.

Learn how to convert APIs into MCP servers using OpenAPI and Stainless. A technical guide to structuring tools, schemas, and workflows when generating MCP servers.

SDKs aren't just wrappers. They shape developer experience, reduce support burdens, and future-proof your API for AI.

Ruby SDK and Terraform provider generators are now generally available, along with major upgrades to MCP, TypeScript, Go, and Java. Our free tier is also expanded to support up to 5 SDKs.

How we handled $refs, client quirks, recursive schemas, and tool selection in a clean, extensible way.

You can now generate MCP servers for free using your OpenAPI spec.

Ensure forwards compatibility in Java SDKs by wrapping enums with a fallback _UNKNOWN case.

How to preserve source and binary compatibility for nullable fields in Java.

We’re excited to share that we’ve raised $25 million in Series A funding. Here's what's next for Stainless.

Stainless generates the official client libraries for OpenAI, Anthropic, Cloudflare, and more. Today, we’re making the Stainless SDK generator available to every developer with a REST API.