companies

Fern

API documentation and SDK-generation platform, now part of Postman, that turns an OpenAPI spec into published docs and typed client libraries.

Fern was started in 2022 by Danny Sheridan, Deep Singhvi, and Zach Kirsch, three engineers who had spent time building and maintaining SDKs by hand and wanted to automate the parts that were always the same: parsing an API spec, generating idiomatic client code across languages, and keeping docs in step with the API itself. The company went through Y Combinator's Winter 2023 batch and built out of Brooklyn, New York, working in person from a Williamsburg office. Fern raised a $9 million Series A in April 2025, led by Bessemer Venture Partners with Y Combinator participating, bringing total funding to roughly $13 million. By early 2026 more than 200 companies, including Square, Webflow, Auth0, Intercom, and ElevenLabs, were using Fern to publish API reference docs and generate SDKs from a single OpenAPI or AsyncAPI source of truth. On January 8, 2026, Postman announced it had acquired Fern, folding the team and product into Postman while keeping the Fern brand, pricing, and roadmap intact for existing customers.

Founded

2022

Headquarters

Brooklyn, United States

Sector

applications