Alternatives
Products that do what Callosum – A smarter OpenAPI editor/client does
A couple years ago I was really frustrated by Postman, it couldn't do basic JSON schema validation, and didn't interoperate well with the OpenAPI spec I had to use for serverless deployments. On top of that, they started requiring an account and cloud sync, and other things I just wasn't comfortable with. So what's an engineer to do? Build yet another API Client of course! [0] It's still fairly rough and crashes more often than I like, but it's basically at the point that I've switched most of my usage so I figured I would rip off the bandaid and do a Show HN. Short list of some of the…
- 1NO
Hello HN! The day has finally come to stop adding features and start sharing what I've been building the last 5-6 months. It's a bit of CrewAI, OpenDevon, LangFuse/Cloud all in one, providing devs who prefer TypeScript an integrated framework thats provides a lot out of the box to start experimenting and building agents with. It started after peeking at the LangChain docs a few times and never liking the example code. I began experimenting with automating a simple Jira request from the engineering team to add an index to one of our Google Spanner databases (for context I'm the…
2024 · github.com
- 2NW
2021 · github.com
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- 4AJ
In my spare time to remind myself that I could actually build stuff (and learn some Python, Flask, Redis, etc) I put together a simple job board to feature the best jobs in the API industry. The jobs can be either building APIs at companies like Twilio, Box, Stripe, etc. or integrating them. In addition to featuring those jobs, I'm also aggregating API jobs from GitHub Jobs, Stack Overflow Careers 2.0, and 37signals Job Board. Today I launched with what I would consider an 'MVP' with jobs from SendGrid, TokBox, Twilio, Zencoder, Parse, Stripe, Pusher and Box. Check it out, I'd love to know…
2012
- 5IV
Hi HN,<p>In my spare time (evenings and weekends) I've built 3 products which have been relatively successful even with little advertising (only google ads budgeted at $30 per day). The latest one is WcfStorm.Rest; which is a REST service test client. I built it because I found that the current tools did not have the features I wanted such as, intellisense when working with HTTP headers, syntax highlighting for JSON messages, etc.<p>I'm continually trying to improve these products and would very much love get your feedback. Every suggestion is welcome!<p>(My apologies…
2012 · wcfstorm.com
- 6IM
I built this library because I kept rewriting the same fetch wrapper for every project. Each time, I needed the same core features: - Make fetch throw errors to integrate smoothly with libraries like TanStack Query - Add sensible defaults to the Fetch API, like a base URL and authentication headers - Validate responses for type safety when OpenAPI isn’t an option I also wanted the library to feel exactly like using fetch — no new API to learn, and no extra friction for my teammates. While there are other great options out there, I found many were either too rigid or too bulky. Doesn’t it…
2025 · github.com
- 7FO
This is a two man team and we're in full-on development of a new platform to assist in multiplayer games. We're looking to launch in about a month or two with an OpenID server accessible to customers (or they can use provider like Facebook/Twitter) and a couple cool multiplayer features. After we launch development will continue until we have a well-rounded API. We're primarily targeting HTML5+JS developers but the system will work with any language that can make RESTful API calls. We know there's some stiff competition out there but we're looking for feedback and what features may make…
2014 · playpi.net
- 8LC
Hey, folks here is a peek into Jujutsu. We at Poozle are working with hundreds of APIs and it has been always frustrating to 1. Search the API in the documentation or ask ChatGPT 2. Then copy it to the postman and understand/test the API 3. Generate code to integrate into the codebase We thought how about having all of this at one place. We currently fine-tuned LLM on public REST APIs to reduce hallucination and then combined it with ChatGPT and Postman. I look forward to feedback, feature requests and discussions!
2023 · loom.com
- 9CA
Hi HN, I've been working with LLMs in production for a while both as a solo dev building apps for clients and working at an AI startup. The one thing that always was a pain was to pay OpenAI/Gemini/Anthropic a few dollars a month just for me to say "test" or have a CI runner validate some UI code. So I built this server called ChunkBack, that mocks the popular llm provider's functionality but allows you to type in a deterministic language: `SAY "cheese"` or `TOOLCALL "tool_name" {} "tool response"` I've had to work in some test environments and give good results for experimenting…
Nov 2025 · github.com
- 10LB
Howdy friends! Tell me if this is an atrociously terrible idea - I've been working on building a leetcode for clientside devs so we can practice React and Javascript interview questions in a more concise way, I call it clientside.dev I just finished a beta version of it yesterday and plan on releasing it with many more problems on Jan 1st but it's there if you wanna play with it open to any ideas / feedback however mean or nice it may be :)
2022 · vacation-call-335691.framer.app
- 11IG
Hey HN! I've been using RabbitMQ for about 10 years now, and while the web UI is handy, I've always found the experience frustrating. We all used to share scripts that would add JSON formatting and other small details to make it more practical. At some point, I even tried proposing improvements or a revamp of the UI on the RabbitMQ Slack. The answer I got was "don't fix what is not broken", which in hindsight was obviously the right one. So I took a different route and built the tool I wished existed: a desktop IDE for RabbitMQ. The key features I started with are: - Multi-connection support…
2025 · rabbitgui.com
- 12BP
Hi all, I'm one of the authors of Serverless-Stack.com — an open source guide to building full-stack apps with AWS Lambda and React. Since it's launch in 2017, it's become one of the most widely read guides for building Serverless apps. Today we are adding a new section to the guide that walks you through the best practices of building large Serverless applications. It tries to address some of the most common questions that teams have: - How should my project be structured when I have dozens of interdependent services? - How should I manage my environments? - What are the best practice for…
2019
- 13RA
Hi HN, I recently open sourced a small tool (Remuda) that I built at work to remove some of the friction of launching and managing agents and figured HN might be interested. I also wrote a post on the company blog that goes into more detail about why I built it and showcases its features: https://www.yendo.com/blog/remuda-an-agent-orchestrator
Jun 2026 · github.com
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- 15RT
rx is a lightweight CLI and runtime that lets you deploy any function instantly as you save it in your editor. It’s fast, simple, and takes care of setting up all your cloud infrastructure. The best dev experience with everything you need built-in: - auth - permissions - payments - secrets - storage - logs - email & SMS - and way more Related beta launch tweet: https://x.com/KhalidZoabi/status/1777673531972608249 Wanted to show it to you guys, gauge interest, and get some feedback. There's a large roadmap of upcoming stuff. Feel free to DM me on X for more information!
2024 · rx.run
- 16CF
Over this past month I had the idea to build a 100% open-source MIT-licensed tool to simplify sharing code with LLMs, without the vendor lock-in you get from most SDKs. Right now, it’s way too hard to export your data or work freely with models like o1 PRO or Grok 3, especially since they don’t even have API access. So I built OpenRepoPrompt, an open-source tool from wildberry-source that serializes files and folders into XML for LLMs. I coded/designed from 12PM -> 11PM on Saturday and 8AM -> 11PM on Sunday. There are still tons of features missing (I'm working on better file filtering…
2025 · github.com
- 17IB
An open-source, headless, API-first platform that empowers developers and product teams to create and optimize custom in-app user flows, such as new user onboarding wizards. Tutim library supports multi-step forms, conditional branching, custom validation, l10n, and more – all through a JSON schema and unlimited flexibility through code. Beta release on GitHub (star us!): https://github.com/tutim-io/tutim. Why it's better than other form builders or open-source libraries? - Flexible: Seamlessly integrate Tutim with your design system components, APIs, and your backend. -…
2023 · github.com
- 18IB
After fine-tuning GPT for a personal project, I realized how tedious it is to write plain text in a massive JSON file. That's why I built this app for my own use, and I want to see if others could benefit from a tool like this as well ;)
2024 · finetuna-ui.com
- 19IB
Hi HN, I’m the creator of Cordum. I’ve been working in DevOps and infrastructure for years (currently in the fintech/security space), and as I started playing with AI agents, I noticed a scary pattern. Most "safety" mechanisms rely on system prompts ("Please don't do X") or flimsy Python logic inside the agent itself. If we treat agents as autonomous employees, giving them root access and hoping they listen to instructions felt insane to me. I wanted a way to enforce hard constraints that the LLM cannot override, no matter how "jailbroken" it gets. So I built Cordum. It’s an open-source…
Jan 2026 · github.com
- 20PR
Hi HN, While building RAG agents, I noticed a lot of token budget was wasted on formatting overhead (HTML tags, JSON structure, whitespace). Existing solutions felt too heavy (often requiring torch/transformers), so I wrote this lightweight, zero-dependency library to solve it. It includes strategies for context packing, PII redaction, and tool output compression. Benchmarks show it can save ~15% of tokens with negligible latency overhead (<0.5ms). Happy to answer any questions!
Dec 2025 · github.com
- 21IB
Hey HN! Over the past few weeks, I’ve been working on DataBridge, an open-source solution for data ingestion and querying across text, PDFs, images, and videos. In our latest update, we’ve added a fully local deployment option: - No internet required – Runs entirely offline. - Customizable Models – Supports any LLM and embedding model via Ollama (with options for any other private providers) - Extensibility – You can plug in your own models or tools easily. This local-first approach ensures better privacy, security, and flexibility, especially for teams dealing with sensitive data. You can…
2025 · github.com
- 22SN
Hey folks, I am finally posting a Show HN post for a project I have been working on for several months now, and it's in a state where I already get a lot of value myself, so I am happy to share broadly. The pitch line is: "Skybear.NET is a managed platform automating Synthetic HTTP API testing." At the moment, the main source file format supported for your API tests are Hurl.dev files [1]. Hurl is a CLI tool wrapping `curl` and it's really awesome. At least check that out :) I am not affiliated directly with the Hurl CLI tool, and the platform I am building provides full Hurl compatibility.…
2024 · skybear.net
- 23BS
i had previously posted this when it was aws-rce. it’s changed enough that i want to post it again.
2022 · github.com
- 24JT
Hi HN; over the last 4 years, we've been building Joist, an ORM for TypeScript & Postgresql, that solves many of the footguns of traditional entity-based ORMs. One of our early adopters challenged us to be less humble in our marketing, and this silly-but-serious blog post is the result. :-) Disclaimer this post assumes a lot of familiarity with ORMs, so that it can focus on how Joist (and the JavaScript + TypeScript stack) has solved these historical issues, but the rest of the Joist docs try to be more tutorial/beginner oriented.
2024 · joist-orm.io
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