Dev tools · alternatives · 2026
24 alternatives to Fern, a language for defining REST APIs that compiles into OpenAPI
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 +…
Fern is a language and compiler for defining REST APIs that automatically generates SDKs, server code, Postman collections, and OpenAPI specifications. Designed for developers who want to spend less time on API… Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes. Fern, a language for defining REST APIs that compiles into OpenAPI launched in 2023; newer entries below may have overtaken it.
- 1
Fern▲260We built the world’s first generated, idiomatic gRPC and REST SDK. If you have public gRPC and REST endpoints, Fern is the SDK provider for you.
2025 · buildwithfern.com · its alternatives →
- 2
Knit API▲3931 to Many API for all customer-facing Integrations
2023 · getknit.dev · its alternatives →
- 3
Nino is a radical approach to solve the app chaos problem for today's knowledge worker. I believe there are still too many tools; even using them becomes work in itself. I'm building all these apps from scratch in one place, using the same database and UI, with the flexibility to eventually support the majority of work from one "superapp." Currently there are 18 apps (called "modules") on Nino: - Database types: Sheet, Form, Calendar, Gallery, Board, Todo, List - Composition types: Doc, Slide, Drive, Notebook, Canvas, Grid, Blog, Site - Communication types: Channel, Chat, Meet I want to…
2024 · nino.app · its alternatives →
- 4
Cannoli Programming Language. Contribute to joncatanio/cannoli development by creating an account on GitHub.
2018 · github.com · its alternatives →
- 5TA
An OpenAPI alternative to describe REST APIs for type-safe code generation.
2023 · typeapi.org · its alternatives →
- 6
Hi, I made a bridge (https://github.com/fzyzcjy/flutter_rust_bridge v2.0.0) between Flutter and Rust, which auto translates syntaxes like arbitrary types, &mut, async, traits, results, closure (callback), lifetimes, etc. The goal is to make a bridge between the two, seamlessly as if working in one single language. Then, as an example, I showed how to write Rust applications with GUI by utilizing Flutter. That is discussed in the link in details. To play with it, please visit the GitHub repo, or refer to the end of the article for detailed folders and commands. When I…
2024 · cjycode.com · its alternatives →
- 7
Instantly generate openapi (OAS) 3.0.0 REST + GraphQL APIs
2019 · github.com · its alternatives →
- 8
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,…
2022 · easysdk.xyz · its alternatives →
- 9
Erlang REST framework. Contribute to fbeline/rooster development by creating an account on GitHub.
2017 · github.com · its alternatives →
- 10
Hey HN, we’re building an open specification that lets agents discover and invoke APIs with natural language, built on the OpenAPI standard. agents.json clearly defines the contract between LLMs and API as a standard that's open, observable, and replicable. Here’s a walkthrough of how it works: https://youtu.be/kby2Wdt2Dtk?si=59xGCDy48Zzwr7ND. There’s 2 parts to this: 1. An agents.json file describes how to link API calls together into outcome-based tools for LLMs. This file sits alongside an OpenAPI file. 2. The agents.json SDK loads agents.json files as tools for an LLM that…
2025 · github.com · its alternatives →
- 11
API design studio for product managers
2023 · conektto.io · its alternatives →
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FastOpenAPI is a library for generating and integrating OpenAPI schemas using Pydantic v2 and various frameworks (AioHttp, Django, Falcon, Flask, Quart, Sanic, Starlette, Tornado). - mr-fatalyst/fastopenapi
2025 · github.com · its alternatives →
- 14
Octri.dev▲136Octri provides API teams a single platform to publish docs, generate SDKs, add MCP access, and monitor APIs in production. API Studio includes editable API docs with Ask the Docs, agent-readable docs, custom guides, code examples, and an API playground. SDK Studio generates clien
Sep 2026 · octri.dev · its alternatives →
- 15AL
2013 · np-lang.org · its alternatives →
- 16
ChunkHound’s goal is simple: local-first codebase intelligence that helps you pull deep, core-dev-level insights on demand, generate always-up-to-date docs, and scale from small repos to enterprise monorepos — while staying free + open source and provider-agnostic (VoyageAI / OpenAI / Qwen3, Anthropic / OpenAI / Gemini / Grok, and more). I’d love your feedback — and if you have, thank you for being part of the journey!
Jan 2026 · github.com · its alternatives →
- 17
Hey HN! We've developed OpenAPI AutoSpec, a tool for automatically generating OpenAPI specifications from localhost network traffic. It’s designed to simplify the creation of API documentation by just using your website or service, especially useful when you're pressed for time. Documenting endpoints one by one sucks. This project originated from us needing it at our past jobs when building 3rd-party integrations. It acts as a local server proxy that listens to your application’s HTTP traffic and automatically translates this into OpenAPI 3.0 specs, documenting endpoints, requests, and…
2024 · github.com · its alternatives →
- 18
Simple online database service in the cloud with NoSQL, REST API, low code javascript hooks, MongoDB support and more. Perfect for API automation, custom development, enterprise, backoffice, serverless backends, database driven websites. It provides easy collaboration and data management with secure
2016 · restdb.io · its alternatives →
- 19
Generate and share OpenAPI specs with AI
2025 · api.dev · its alternatives →
- 20NanoAPI Cloud▲128
A dependency map of your code that shows where to refactor
2025 · its alternatives →
- 21
Hey there HN! I just wrapped up an all-day documentation spree for Instant API, a JavaScript framework for easily building web APIs that implements type safety at the HTTP interface. It uses a function-as-a-service approach combined with a slightly modified JSDoc spec to automatically enforce parameter and schema validation before HTTP requests make it through to your code. You just write comments above your endpoint functions and voila, enforced type safety contracts between your API endpoints and your developers. OpenAPI specifications are generated automatically as a byproduct of simply…
2023 · github.com · its alternatives →
- 22
🍐 The enterprise REST API framework. Contribute to go-goyave/goyave development by creating an account on GitHub.
2020 · github.com · its alternatives →
- 23
Developerhub.io▲149Create beautiful powerful documentation, hassle-free.
2018 · developerhub.io · its alternatives →
- 24
SlashApi is a web platform to build REST APIs fast without having to write any code yourself, you will gain instantly access to a fully operational API
2021 · slashapi.com · its alternatives →
Also compare
- Fern alternatives
- Knit API alternatives
- I made an app that consolidated 18 apps (doc, sheet, form, site, chat…) alternatives
- Cannoli – A compiler for a subset of Python written in Rust alternatives
- TypeAPI – An OpenAPI alternative optimized for code generation alternatives
- Rust GUI Library via Flutter alternatives
Ranked by how close each launch is in meaning, then by votes. Prices were read from each product’s own site when checked and can change. Refine with your own description →