nowfound

AI · alternatives · 2026

24 alternatives to Turn OpenAPI to Universal TypeScript SDKs

Hi HN! We’re excited to share our new code generator that lets you ship high-quality TypeScript SDKs, that your users will love, from your OpenAPI documents. Our ongoing goal is to help you build one SDK that runs anywhere modern JavaScript runs. This includes new runtimes like Deno and Bun in addition to the ever-popular Node.js. Additionally, the popularity of AI has meant server-sent events and file streaming are also commonplace - we wanted to cover these use cases too. This explosion in new runtimes and ways of interacting with APIs shifts cognitive burden on API developers often having…

A code generator that transforms OpenAPI documents into TypeScript SDKs compatible across multiple JavaScript runtimes including Node.js, Deno, and Bun. The tool is designed for API developers who need to support… Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes. Turn OpenAPI to Universal TypeScript SDKs launched in 2024; newer entries below may have overtaken it.

  1. 1

    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 →

  2. 2

    Effortlessly discover API behaviour with a Chrome extension that automatically generates OpenAPI specifications in real time for any app or website.

    2023 · github.com · its alternatives →

  3. 3

    Handwritten SDKs generated from OpenAPI

    2024 · speakeasy.com · its alternatives →

  4. 4

    Hi Hacker News! Patrick and Elias here. We built an SDK / Documentation generator for REST APIs. The link included shows the shiny output of our system: the docs! We generated 5 SDKs and docs from the Hacker News OpenAPI we found on GitHub. If you write code in Python, Typescript, Go, Ruby, or Rust, we’d love for you to try an SDK out! If you want to generate SDKs for your own API try our tool here: https://github.com/Sideko-Inc/sideko We are both software engineers, and we built this tool because we were spending too much time writing API integrations, supporting…

    2023 · hacker-news.sideko.dev · its alternatives →

  5. 5
    Fern▲260

    We 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 →

  6. 6TA

    An OpenAPI alternative to describe REST APIs for type-safe code generation.

    2023 · typeapi.org · its alternatives →

  7. 7
    Bun▲295

    A fast JS runtime Node.js replacement with built‑in tools

    Dec 2025 · bun.com · its alternatives →

  8. 8

    Really good SDKs from OpenAPI

    2025 · sideko.dev · its alternatives →

  9. 9

    Instantly generate openapi (OAS) 3.0.0 REST + GraphQL APIs

    2019 · github.com · its alternatives →

  10. 10

    Generate production-ready SDKs from OpenAPI specs instantly

    Jul 2026 · sdkcraft.com · its alternatives →

  11. 11

    Hi HN, I’m Patrick. Elias, Kevin, and I are building Sideko (https://sideko.dev), a new type of code generator for building and maintaining API client SDKs from OpenAPI specs. Traditional SDK generators rely on static templates that produce rigid, machine-generated code. When the API changes, these generators completely overwrite the SDK, destroying any custom modifications developers have made. The result is brittle code that looks artificial and requires constant manual rework. Our approach uses structured pattern matching queries instead of templates. These queries analyze the…

    2025 · github.com · its alternatives →

  12. 12

    A generator for OpenAPI 3. Contribute to egorsmkv/openapi3-generator development by creating an account on GitHub.

    2020 · github.com · its alternatives →

  13. 13

    Generate and share OpenAPI specs with AI

    2025 · api.dev · its alternatives →

  14. 14

    Colin here, creator of Nub. I’ve had the general shape of this in mind for years. Nub runs your code with stock `node`, augmented with a `--require` preload hook[0] that adds a transpiler (oxc-powered, packaged as a Node-API add-on), registers a module resolution hook[1], and injects polyfills as needed for APIs like `Worker`, `Temporal`, etc. All purely additive, your code ultimately runs using Node’s actual engine & stdlib implementations. [0] https://nodejs.org/api/cli.html#-require-module [1]…

    Jun 2026 · github.com · its alternatives →

  15. 15

    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 →

  16. 16

    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 →

  17. 17

    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 →

  18. 18

    Hey, I'm Martyn and I recently joined Zuplo. OpenAPI is a huge part of what we do, but getting a document up to scratch out of the gate, especially if you're not super well versed in the actual specification and what you should use and when. So we built a suite of tools to help with this called Rate My OpenAPI. It will score your OpenAPI document out of 100, as well as giving you individual scores in 4 key areas; completeness, SDK generation, security and documentation. Along with the score, you also get details of what the issues, or errors are, as well as guidance on what they actually…

    2024 · github.com · its alternatives →

  19. 19

    We built an open-source tool that scans your codebase and generates OpenAPI docs in minutes. Right now it supports Rails, Go, Python, and NodeJS frameworks, and we will keep adding more. It picks up routes, params, request bodies, and models directly from the code and outputs a clean OpenAPI spec you can drop into your workflow.

    Nov 2025 · github.com · its alternatives →

  20. 20

    Types generator will auto generate TS Interfaces from JSON

    2022 · vineethtrv.github.io · its alternatives →

  21. 21

    Hello all To preface this is just something I've been making as a learning exercise, so all feedback is appreciated. This is a tool that converts JSON schemas into TypeScript utility classes for use in Deno. Automatic Type Generation: Typescript interfaces for the compressed and uncompressed versions of your data. Compression & Decompression: Compress and decompress your data. Validation: Built-in data validation using Ajv ensures your data adheres to the schema. Reusability: Once generated, the utility classes can be used in other Deno projects. It currently only supports a subset of JSON…

    2023 · github.com · its alternatives →

  22. 22
    Konfig▲87

    Generate SDKs, docs, demos & tutorials for your REST API

    2023 · konfigthis.com · its alternatives →

  23. 23
    JS20▲12

    Build TypeScript backends and SDKs with up to 90% less code. Faster, cheaper & easier to maintain. Ready for the AI era, less code = less tokens & reduced costs.

    Oct 2025 · js20.dev · its alternatives →

  24. 24

    Hey everyone! Over the past two years I threw myself back into full-time engineering with a simple goal: write code that gives back to the community. After a lot of late-night FOMO (“AI will do it all for us, right?”) and some painful production incidents, I finally turned my weekend project into an open-source library. [ What is Solidis? ] - Super-light (< 30 KB) RESP2&#x2F;RESP3 client with zero runtime deps and first-class ESM&#x2F;CJS support. - Fully tree-shakable – import only the commands you need. - Written with SOLID principles & full TypeScript typings for every command. - Designed…

    2025 · github.com · its alternatives →

Also compare

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 →