Fern

Beautiful API docs and production-ready SDKs from your API spec.

Hand-reviewed by the Toolglade team·Updated Aug 2026

coding#api-docs#sdk-generation#developer-tools#documentation

Free plan API Teams

Toolglade’s take

Fern is one of the strongest tools for turning an API spec into both polished docs and genuinely usable, production-ready SDKs across many languages, which is a real time-saver for developer-facing companies. The big context for 2026 is that Postman acquired Fern in January; Postman says the product stays independent with the same brand and roadmap, and the team joined intact, but any acquisition adds uncertainty about long-term direction and pricing. Evaluate it on its still-excellent product while keeping the ownership change in mind.

About Fern

Fern generates polished API documentation and production-ready SDKs in many languages from an API definition, keeping both in sync with the source of truth. It supports TypeScript, Python, Go, Java, C#, PHP, and Ruby and builds branded docs sites. A Y Combinator company acquired by Postman in January 2026, Fern continues as an independent product and serves many developer-facing companies that want a first-class developer experience for their APIs.

Fern (buildwithfern.com) helps companies ship hand-crafted-feeling API documentation and production-ready SDKs without maintaining them by hand. From an API definition, Fern generates SDKs across languages including TypeScript, Python, Go, Java, C#, PHP, and Ruby, and builds customizable, branded documentation sites. It targets teams that want their API to feel first-class to developers, with SDKs and docs that stay in sync with the spec. Fern was a Y Combinator company that raised a Series A led by Bessemer, and on January 8, 2026 it was acquired by Postman. Postman positioned the deal as strengthening the last mile of API programs, and stated that Fern would continue to operate as an independent product with the same brand, roadmap, and team. Since launching in 2023, Fern has served a large roster of customers, including well-known developer-facing brands. Fern competes with Mintlify, ReadMe, Stainless, and Speakeasy in the API-docs-and-SDK space. Its strengths are SDK generation quality and the combination of docs plus SDKs from one source of truth. The main consideration for buyers is the post-acquisition trajectory: while Postman has committed to independence, teams should watch how the product integrates over time.

TL;DR

Fern generates polished API documentation and production-ready SDKs in many languages from an API definition, keeping both in sync. A Y Combinator company that raised a Series A led by Bessemer, Fern was acquired by Postman on January 8, 2026 and continues as an independent product. It serves over 200 developer-facing customers. Pricing spans a free tier and paid Basic, Pro, and Enterprise plans, with limited public detail.

Company overview

Fern is a developer-experience company founded around 2022 and backed by Y Combinator, which raised a Series A led by Bessemer Venture Partners, bringing total funding to roughly $13 million. On January 8, 2026, Postman acquired Fern for an undisclosed amount.

Postman, which serves more than 500,000 organizations, framed the acquisition as improving the last mile of API programs. Fern stated it would continue as an independent product with the same brand, roadmap, and team joining Postman.

Product features

Fern turns an API definition into production-ready SDKs across TypeScript, Python, Go, Java, C#, PHP, and Ruby, and builds customizable, branded documentation sites from the same source of truth. It automates the ongoing maintenance of SDKs and docs as the spec evolves.

The combination of docs plus SDKs from one definition is Fern's core differentiator, reducing the manual work of keeping client libraries current. Deployment is via Fern's cloud rather than self-hosting.

Target market

API-first companies, developer-experience teams, and engineering organizations that publish public APIs and want first-class SDKs and docs.

Buyer personas

End users

Developers who consume the generated SDKs and read the docs, plus the technical writers and DX engineers who maintain them.

Buyers

Engineering leaders and developer-experience managers at API-first companies.

Key influencers

Developer advocates, platform teams, and the broader Postman ecosystem.

Ideal customer profile

A company with a public, spec-driven API that wants automated, high-quality SDKs and branded docs and is comfortable being part of the Postman ecosystem.

Funding & performance

Raised a $9 million Series A led by Bessemer Venture Partners, bringing total funding to roughly $13 million. Acquired by Postman on January 8, 2026 for an undisclosed amount.