Postman and Insomnia Alternatives

In plain words

This is an open-source alternative to API testing tools like Postman and Insomnia. It provides developers and technical teams with a way to build, test, and debug APIs without relying on commercial platforms. The tool is available on GitHub for anyone to use, modify, and contribute to, making it accessible to those seeking open-source solutions for API development workflows.

written from the facts on this page · September 2026

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

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

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  Restfox – Open source lightweight alternative to Postman2022 · restfox.dev · ▲758

  Last time I posted this it didn't garner much interest. There have been lots of improvements and fixes since the last release. Quick list of features: - Workspaces - Tabs - Nested Folders - Lots of context menus - Response history - Plugins - Runs fully in the browser and runs offline if necessary - Chrome and Firefox extension to bypass CORS restrictions - Desktop builds for all platforms - GraphQL support - Import collections exported from Postman and Insomnia - Simple user friendly interface I built this because I love Insomnia but wanted a portable version that I could run in the…

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  Insomnia Designer – Open-source collaborative editor for API design2020 · insomnia.rest · ▲317

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

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  Insomnia REST API Client2015 · insomnia.rest · ▲112

  Build, manage, and run templated REST API requests

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  Yaak – An open source, Git-friendly desktop API client2025 · yaak.app · ▲153

  Hi HN! I'm Greg and I've been working on Yaak for just over a year. I usually describe it as a Postman alternative since most developers are familiar with that, but it's targeted more toward users that just want an API client (no mocking, testing, spec design, etc). Having also created Insomnia for a similar purpose, I never thought I'd build another API client again. But, after selling Insomnia in 2019 and watching it expand into the broader feature set of Postman, I was left wanting a simpler tool again. Yaak was my answer to that. It's hard to describe how it's better than the 100 other…

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  Postman2014 · postman.com · ▲182

  Postman is a powerful HTTP client to test REST API

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  /dev/null▲482

  a social network for devs

  Dev tools · 3d ago · dev-null.sh

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  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

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  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

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  OpenBot▲362

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

  Dev tools · 23d ago · openbot.run

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  Talanoa▲346

  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

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  CoreSpeed▲332

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

  Dev tools · 28d ago · corespeed.io

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  AI Content Genie▲1,071

  AI autopilot for content creation & marketing

  AI · 2023 · typeface.ai

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  Nudge 2.0▲1,051

  In-app experiences to activate, retain, & understand users

  Growth · 2023 · nudgenow.com

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  Cal.ai Email Assistant▲918

  World's first open source AI scheduling assistant

  AI · 2023 · cal.com

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  Design Studio by Tiledesk▲867

  Unlock AI magic for elevated customer engagement, fast

  AI · 2023 · tiledesk.com

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  TalkNotes▲854

  Turn your thoughts into actionable notes, fast

  AI · 2023 · talknotes.io

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  OpenAPI DevTools – Chrome extension that generates an API spec▲811

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

  Dev tools · 2023 · github.com