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Fern

Fern

Input OpenAPI. Output SDKs and Docs.

APIs underpin the internet but are still painful to work with. They are often untyped, unstandardized, and out-of-sync across multiple sources of truth. Fern enables businesses to offer “Stripe-level” SDKs (client libraries) and Docs for their REST API. Inspired by internal tooling we saw at AWS and Palantir, we’re building Fern to let every engineering team offer easy-to-use and well-documented APIs. Founded in 2022, we’re less than 10 people, building open source, and backed by YCombinator. We work together in our office in the Williamsburg neighborhood of Brooklyn, NY. Our customers include Cohere, ElevenLabs, Webflow, and Merge.dev.

Jobs at Fern

NY, US
$156K - $192K
3+ years
NY, US
$156K - $192K
3+ years
New York, NY, US
$156K - $192K
3+ years
Fern
Founded:2022
Team Size:6
Location:New York
Group Partner:Brad Flora

Active Founders

Danny Sheridan

Hey- I'm a co-founder and CEO at Fern. At my previous role at AWS, I saw how code generation for APIs saved engineering time and offered a best-in-class developer experience. I'm a people person who is happiest at work when collaborating in person or when hearing customer lover first-hand.

Danny Sheridan
Danny Sheridan
Fern

Deep Singhvi

Deep is a YAML engineer at Fern. Before Fern, he worked as a software engineer at Palantir focusing on data integration at the Department of Defense and US Army.

Deep Singhvi
Deep Singhvi
Fern

Company Launches

TLDR: Fern generates useful artifacts for your API, like SDKs, docs, and server code. Star us on GitHub! ⭐

Steve Yazicioglu, Head of Engineering at Candid Health (Series A)

Problem

When building APIs, we spent a lot of our time doing things like:

  • Writing types & networking logic on the backend
  • Communicating details of the API endpoints over Slack
  • Re-writing the same types & networking logic on the frontend
  • Re-writing the same types & networking logic in each SDK or client library
  • Re-writing the same information in our docs & Postman Collection

Inevitably, these multiple sources of truth get out of sync, causing runtime bugs, wasted hours of debugging, and frustration.

Solution

Fern productizes schema-first API design. You define the schema of your API (or give us an OpenAPI spec) and we generate:

  • SDKs in popular programming languages. Our SDKs feel handwritten. They can be used externally for customers or internally for your frontend/microservices.
  • API docs that sync to your provider of choice.
  • Postman Collection complete with examples of successful and unsuccessful requests
  • Server-side validation to make sure that you serve the API you promised.

Fern also registers all versions of your API in a registry — no need to ping a coworker over Slack to understand how to consume an API.

With love 💌,
Team Fern 🌿 (Deep, and Danny)

Our asks

What our users are saying

YC Sign Photo

YC Sign Photo