Fern

Fern

Open-source platform automating REST API development

About Fern

Simplify's Rating
Why Fern is rated
B+
Rated B on Competitive Edge
Rated A on Growth Potential
Rated B on Differentiation

Industries

Consumer Software

Enterprise Software

Company Size

51-200

Company Stage

Series A

Total Funding

$9.6M

Headquarters

Seattle, Washington

Founded

2023

Overview

Fern is an open-source platform that helps developers build REST APIs faster by automating the boring parts of API creation. It speeds up development by about 50% and is designed to work in real production environments, with companies like Raven using it to auto-update SDKs and docs whenever an API changes. Fern’s SDKs are designed to feel handwritten and idiomatic, even though they’re generated, and it supports multiple languages and frameworks. It also takes care of publishing SDKs to GitHub and other registries, and provides a Postman Collection with examples, plus an OpenAPI specification that works with many tools. Fern’s goal is to let developers focus on business logic instead of boilerplate while delivering production-ready API tooling across languages and ecosystems.

YC Company
Simplify Jobs

Simplify's Take

What believers are saying

  • Postman acquisition grants access to 40 million developers worldwide.
  • Self-hosted Docker images enable enterprise on-premise deployments.
  • Over 200 companies including Square and Twilio actively use Fern.

What critics are saying

  • Postman integration fails, causing Fern team autonomy loss and customer exodus.
  • Speakeasy overtakes with superior AI SDKs, eroding Fern's customer base.
  • OpenAI's free SDK generator launches, obsoleting Fern for cost-sensitive users.

What makes Fern unique

  • Fern generates idiomatic SDKs in nine languages from OpenAPI specs.
  • Fern produces customizable docs with AI search and API playground.
  • Fern supports AsyncAPI, Protobuf, OpenRPC beyond REST APIs.

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Funding

Total Funding

$9.6M

Below

Industry Average

Funded Over

2 Rounds

Series A funding typically happens when a startup has a product and some customers, and now needs funding to scale. This money is usually used to grow the team, expand marketing, and improve the product. Venture capital firms are frequently the main investors here.
Series A Funding Comparison
Below Average

Industry standards

$15M
$8.2M
Discord
$9M
Fern
$15M
Canva
$30M
Kalshi

Benefits

Health Insurance

Dental Insurance

Vision Insurance

Unlimited Paid Time Off

Meals (breakfast, lunch, and dinner)

Company News

FinSMEs
Jan 8th, 2026
Postman Acquires Fern

Postman acquires Fern. Postman, a San Francisco, CA-based API collaboration platform provider, acquired Fern, a NYC-based developer experience company focused on helping businesses ship polished API documentation and production-ready Software Development Kits (SDKs). The acquisition strengthens Postman's commitment to improving how APIs are built, documented, and consumed. The entire Fern team is joining Postman to continue building Fern. The product, brand, and roadmap remain the same, with the same experience assured for customers. Through Postman, Fern will have the opportunity to reach more than 500,000 companies worldwide. Led by Danny Sheridan, co-founder, Fern has built a set of tools for developers consuming APIs. Fern Docs enables teams to create customizable documentation that evolves alongside their API, while supporting modern docs-as-code workflows and enterprise deployment needs. The Fern SDK Generator helps API teams offer idiomatic, production-ready SDKs across nine major programming languages, eliminating the need to manually build and maintain client libraries. Today, more than 200 companies including Square, Auth0, Adobe, Twilio, and ElevenLabs use Fern to drive adoption of their public APIs. Led by Abhinav Asthana, CEO, Postman provides an API collaboration platform to more than 40 million developers and 500,000 organizations. The company streamlines API and AI application development and drive innovation through teamwork by transcending traditional testing and fostering team collaboration across the entire API development lifecycle - from creation to deployment. The company is headquartered in San Francisco with offices in Bangalore, Boston, New York City, and Tokyo. Postman is privately held, with funding from Battery Ventures, BOND, Coatue, CRV, Insight Partners, and Nexus Venture Partners.

Pulse 2.0
Jan 8th, 2026
Postman acquires Fern to expand API documentation and SDK capabilities

Postman has acquired Fern, a developer experience company specialising in API documentation and SDK generation, though financial terms were not disclosed. The deal aims to enhance Postman's API collaboration platform as companies increasingly treat APIs as products. Founded in 2022 and based in New York, Fern offers two core products: Fern Docs for customisable API documentation and Fern SDK Generator, which produces client SDKs across nine programming languages. More than 200 companies, including Square, Auth0 and Twilio, use its tools. The entire Fern team will join Postman whilst maintaining Fern's existing product, brand and roadmap. Postman's platform serves over 40 million developers and approximately 500,000 organisations worldwide, including 98% of the Fortune 500, providing Fern with significant distribution reach.

The American Bazaar
Apr 21st, 2025
Fern raises $9 million Series A to improve developer and agent experience

Fern raises $9 million Series A to improve developer and agent experience.

SiliconANGLE Media
Apr 10th, 2025
Fern secures $9M to automate SDKs

Fern, a startup focused on automating SDK creation and maintenance, raised $9M in a Series A round led by Bessemer Venture Partners and Y Combinator, totaling $13M raised. Fern's AI-driven tools generate and update SDKs and documentation in multiple languages, enhancing developer experience. Their offerings are used by over 150 enterprises, including Square and Webflow. Fern plans to launch an AI assistant, Ask AI, and is preparing tools for future AI agent integrations.

TechCrunch
Apr 5th, 2023
Our favorite startups from YC's Winter 2023 Demo Day — Part 1

Comics software, meat-based plants and Tesla spun-out heat pumps, anyone?

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