Fern

In plain words

Fern is a developer tool that generates software development kits and API documentation from existing API specifications. It supports REST APIs defined in OpenAPI format, WebSocket APIs using AsyncAPI, and gRPC APIs built with Protobuf. Users can customize the generated documentation to match their brand. The tool automatically creates SDKs in multiple programming languages, eliminating manual code generation and keeping documentation in sync with API changes.

written from the facts on this page · September 2026

From the sources

Start with an API spec. Generate SDKs in multiple languages and interactive API documentation tailored to your brand. Support for REST (OpenAPI), WebSockets (AsyncAPI), and gRPC (Protobuf) APIs.

• 
  Fern, a language for defining REST APIs that compiles into OpenAPI2023 · github.com · ▲18

  Hi HN, this is Danny, Deep, and Zach. We built Fern after our previous ed tech startup failed. We were frustrated with how much time we spent writing “API code” instead of working on the actual product. We tried to use OpenAPI but we were underwhelmed - the generated code wasn’t idiomatic and it still required manual work (custom templates, scripts, manually publishing SDKs to registries). The Fern compiler takes your API as input and invokes generators that output things like: SDKs, server code, a Postman collection, and an OpenAPI spec. Some technical highlights about the compiler +…

• 
  Conektto API-First Design Studio2023 · conektto.io · ▲157

  API design studio for product managers

• 
  An opinionated and statically-typed TypeScript SDK generator2022 · easysdk.xyz · ▲81

  Hi Hacker News! My name is Sagar, I’m working on a startup called Speakeasy - we’re making all APIs self-service. The platform is currently in beta, but we’re independently launching this tool which you can use to generate language-idiomatic, statically-typed TS SDKs from any public OpenAPI schemas. We hope to continue iterating on this to give devs a way to easily generate high fidelity client SDKs for all the major languages. Inspiration for this product is from past experiences struggling with OpenAPI. I was originally optimistic about using the OpenAPI tools to build out our offering,…

• 
  create-api.dev by Kong2025 · api.dev · ▲150

  Generate and share OpenAPI specs with AI

• 
  Insomnia REST Client now open-source2017 · insomnia.rest · ▲218

  Leading Open Source API Development Platform for HTTP, REST, GraphQL, gRPC, SOAP, and WebSockets

• 
  DevPod – Codespaces but Open Source, Client-Only, and Unopinionated2023 · github.com · ▲71

  Hi everyone - Looking for feedback for this new open source project we launched. It's called DevPod and it's built on the devcontainer.json standard to create reproducible dev environments. It lets you spin up dev environments in any infra, kind of like a Terraform but for dev environments. Compared to hosted services such as Github Codespaces, JetBrains Spaces, or Google Cloud Workstations, DevPod has the following advantages: - Open Source: DevPod is 100% open-source and extensible. A provider doesn’t exist? Just create your own. - Client-only: No need to install a server backend. DevPod…

• 
  /dev/null▲468

  a social network for devs

  Dev tools · 2d ago · dev-null.sh

• 
  Whiteboard (YC W26) – an open-source IDE for thoughtful software design▲423

  open-source IDE for thoughtful software design. Contribute to devdotfast/whiteboard development by creating an account on GitHub.

  Dev tools · 27d ago · github.com

• 
  Reladraw – A diagram language where you decide where to place things▲411

  Contribute to reladraw/reladraw development by creating an account on GitHub.

  Dev tools · 25d ago · github.com

• 
  OpenBot▲362

  Grok Bot alternative: free, local, open-source, multiplayer

  Dev tools · 22d ago · openbot.run

• 
  Talanoa▲340

  Hi HN, I’m a fullstack developer, and honestly, I’ve lost count of how many side projects I’ve worked on over the years. But one idea kept coming back to me: a different kind of email client. It first came to me in 2014: “What if we could handle emails more like conversations?” Every year, I’d revisit this concept in my “Build Notes.” Ten years later, no one had built exactly what I had in mind — so I finally decided to do it myself. That’s how Talanoa was born. I wanted something focused on people, not timelines. I was tired of marking messages as unread just to remember to reply later, or…

  Dev tools · 20d ago · talanoa.email

• 
  CoreSpeed▲332

  One MCP for everything your agents need: apps, memory, tools

  Dev tools · 27d ago · corespeed.io

• 
  YouMind▲1,223

  The first AI creation studio where learning meets writing

  AI · 2025 · youmind.com

• 
  A store that generates products from anything you type in search▲1,184

  The site hit #1 on HN about a year ago. Got enough traffic that I turned it into a proper API. What's there: - REST API — 35k products, manually filterable by category, free key, 60 req/min - CLI — npx anycrap random -c food - faker.js plugin — bundled, no API call, works offline - HuggingFace dataset — full 35k rows for ML/training https://anycrap.shop/developers

  AI · 2025 · anycrap.shop

• 
  Term.everything – Run any GUI app in the terminal▲1,094

  I made a built-from scratch Wayland Compositor to display any GUI app* in the terminal! I think there is a lot of unexplored potential in custom Wayland compositors, a lot of really cool things you can embed existing applications into! So, I started with embedding apps into the terminal because that is the easiest input/output (output is just utf-8 and I use the great `chafa` library for that, and I just read from stdin for the input). If you have any other ideas for cool Wayland compositors, let me know. I purposedly wrote 80% the app in Typescript to appeal to the most developers and…

  Dev tools · 2025 · github.com

• IR
  I recreated Windows XP as my portfolio▲1,032

  Years ago I stumbled across a basic version of this concept and it stuck with me. I knew if I was ever going to take on such a project, it would need to be flawless, but without coding experience it was just another idea that would never happen. By the end of 2024, as AI coding tools exploded everywhere, I finally had a way to make it real. I started from zero knowledge and spent months collaborating with AI agents as a learning experience. Every pixel and every function went through me. The AI translated what I asked for into code, but every decision was human. I didn't use existing OS…

  AI · 2025 · mitchivin.com

• 
  Ada▲910

  Your own AI data analyst

  AI · 2025 · ada.im

• 
  VidAU - AI Video▲868

  Turn Product Images into Scroll-Stopping Video Ads

  Growth · 2025 · vidau.ai