Alternatives
Products that do what I made a JSFiddle-style playground to test and share prompts fast does
I built this out of frustration as I lead the development of AI features at Yola.com. Prompt testing should be simple and straightforward. All I wanted was a simple way to test prompts with variables and jinja2 templates across different models, ideally somthing I could open during a call, run few tests, and share results with my team. But every tool I tried hit me with a clunky UI, required login and API keys, or forced a lengthy setup process. And that's not all. Then came the pricing. The last quote I got for one of the tools on the market was $6,000/year for a team of 16 people in a…
- 1WW
I spent a few hours last weekend testing whether AI can replace code by executing directly. Built a contact manager where every HTTP request goes to an LLM with three tools: database (SQLite), webResponse (HTML/JSON/JS), and updateMemory (feedback). No routes, no controllers, no business logic. The AI designs schemas on first request, generates UIs from paths alone, and evolves based on natural language feedback. It works—forms submit, data persists, APIs return JSON—but it's catastrophically slow (30-60s per request), absurdly expensive ($0.05/request), and has zero UI…
Nov 2025 · github.com
- 2MA
hi all, I've always wanted to make my own game, but couldn't afford a thousand-dollar adobe (flash+photoshop) license. I'm not a talented programmer, have no degree in CS. But I understand some elements of design. So I got me a copy of ImpactJS, and after about 5 months of steep learning curve (at least for me), I managed to come up with a game. I also integrated it with a highscore and badge system, similar to what you get at Kongregate. You need to login with Google/OpenID to earn badges/scores. link is: http://www.hotbazooka.com/privatejoe hope to hear some feedback/questions from you guys!
2011 · hotbazooka.com
- 3TI
Hi HN! My name is Nick and this is my fun side project. Please lay it on me. HN can think of Tips.io as a cracked out Tailwind Playground that has page management and amazing AI integration. There are a few core ideas: 1) The HTML is the CMS There are no fields or restrictions. Just hover, click, and start tweaking any HTML. Also, certain elements you click will have special easy edit abilities: - auto creates an uploader, stock photo picker (or HTML) - auto creates an uploader, stock video picker (or HTML) - auto creates a big icon picker (or HTML) - auto creates a WYSIWYG Editor (or HTML)…
2024 · tips.io
- 4CL
Hi HN! Run it: OPENROUTER_API_KEY="sk" npx bff-eval --demo We built a tool to help people take LLM outputs and easily grade them / eval them to know how good an assistant response is. We've built a number of LLM apps, and while we could ship decent tech demos, we were disappointed with how they'd perform over time. We worked with a few companies who had the same problem, and found out scientifically building prompts and evals is far from a solved problem... writing these things feels more like directing a play than coding. Inspired by Anthropic's constitutional ai concepts, and amazing…
2025 · github.com
- 5IB
Hi HN, After watching a lot of Show HN's here, it's finally my turn to show something. This is the first real project I have shipped, so it is extra special to me. For those who will inevitably ask why I made yet another mockup editor I covered it on our blog (http://blog.mocktailsapp.in/why-build-yet-another-mockup-editor-tm). Not all the features mentioned in that post have been implemented yet. As such Mocktails is pre-beta software and very minimal. It does not even have user accounts or any actual server side component at all for that matter (yet)! Our intention is to build Mocktails…
2012
- 6
- 7IB
Hi HN, I'm pleased to share Promptspot, an open-source (Apache License 2.0) project that helps automate testing of large language model (LLM) prompts against an array of input data. Modern LLMs offer an enormous amount of leverage if you "teach the bot to fish" — i.e. simply prompt it with both a "system prompt" (which typically doesn't change often) and a dynamic input, which is often application state, search results, recent activity, user profile data, etc. Existing playgrounds and prompt management systems often lack the rigor and flexibility required for this dynamic approach — and as…
2023 · github.com
- 8OS
Hi HN, We're a small team building AI tutors out of India, and as you might guess, this means we spend a ton of time writing, testing, and refining prompts for LLMs. When we started out, we were using the OpenAI playground but things became tedious when we wanted to compare responses from different models. We tried a bunch of other playgrounds but found them lacking in some features so we built our own. Quick Links: Github: https://github.com/supernova-app/ai-playground Hosted demo: http://playground.getsupernova.ai Demo video:…
2025 · playground.getsupernova.ai
- 9IM
Also inspired by this HN submission: https://www.chiark.greenend.org.uk/~sgtatham/quasiblog/findl... The model is gpt-4o-mini-2024-07-18.
2024 · app4.hc11.org
- 10EL
Hey HN! I built Experiment to solve a common frustration in LLM development: the lack of proper tools for prompt engineering experimentation. Here's what makes it different: Key Features: - Load and edit chat completion logs from CSV files - Fork and modify specific conversation entries - Run inference via Anthropic, Mistral, and OpenAI - Define custom tools using JSONSchema format - Visual tool usage analysis with collapsible, sorted key-value pairs - Full mobile support and available as installable PWA Technical Highlights: - Built with React using custom isomorphic architecture -…
2025 · github.com
- 11IV
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
- 12IF
So, after many years of kicking about little apps and not putting the full effort in, I decided to bite the bullet and get on with it. Very much inspired by patio11 and Bingo Card Creator, I present Griddol (http://www.griddol.com) a tool to create and play word searches. Intended mainly for teachers, but encouraging those who like a word search too. This been churning around in my head for over a year in various forms, and I used the concept to help learn CoffeeScript, CouchDB and node.js, so even if the product itself is a failure, the learning process has been valuable. I'll be the first…
2011
- 13AD
Hi all, I threw together a small prototype I am calling “Notepad.ai”. A new take on UIs for interacting with LLMs. While I enjoy using LLM’s in the chat format I wanted to see what it would be like to do it in a more long form style. It let’s you write in a pretty free form, much like Window’s Notepad, but you can choose to hit ctrl+[ to analyze the text with a preset prompt of your choosing. It has a few other small features. It’s WIP and very experimental. I would appreciate any feedback or thoughts. Video: https://youtu.be/ntdlgFmSxQY Live Demo:…
2024 · github.com
- 14IB
Hey HN, I'm Damiano Rodriguez, and I've been working solo on a project called Caisual Games. It's a free platform where anyone can create web games just by describing them with their voice. Here's how it works: You simply describe your game idea ("Make a cookie clicker game with 5 upgrades"), and the platform generates a playable web game in seconds using HTML and JavaScript. There's no coding required and no downloads needed—you can create and play directly in your browser. What's more, anyone can improve a published game, fostering a collaborative environment for game creation. The…
2024 · caisual.com
- 15IB
I built a tool to roast landing pages with AI agents. I was gathering feedback from watching landing page roast videos, and figured out I could prompt LLMs to analyse a screenshot and roast based on the same criteria. It's not 100% accurate yet, but it has been really insightful when I've tested it on my own websites. Let me know what you think!
2024 · roastmylandingpage.io
- 16IB
Hi HN I built a fun little tool: It uses Groq’s LLaMA 3.3 + Puppeteer to analyze a website Then it roasts the design/content/UX with humor And finishes with 3–5 genuinely helpful improvement tips You can try it here: https://ai-roast-vert.vercel.app I wanted to: Practice fast idea-to-launch cycle (built in 2 days) Experiment with a viral-friendly product Monetize with a $0.55 pro version that gives a detailed roast + download Would love your feedback — on the idea, the tone, the usefulness — anything! Thanks in advance
Sep 2025 · ai-roast-vert.vercel.app
- 17FS
Hey HN, Bootstrapped founder here. I've got a bit of a story for you. We started desplega.ai to build a sophisticated AI platform that could automate E2E testing. We spent the last few months talking to dozens of QA leaders, and trying to learn what are their actual challenges. We've got one consistent feedback from large teams: their daily reality is a living hell of slow, clunky tools. We're talking about teams at major companies still managing tests on spreadsheets. Or they're stuck in a Jira instance so customized and slow you can “make a full pot of coffee” while a page loads (and…
Sep 2025 · tester.desplega.ai
- 18IB
So I've been obsessed with a weird question for the past 6 months, what happens to SEO when everyone starts asking ChatGPT for recommendations instead of Googling? The answer, apparently, is chaos. And maybe opportunity? I built FirstClick because I noticed something strange. My previous startup was getting zero traffic from AI assistants, but our competitor (objectively worse product, sorry not sorry) was getting mentioned by Claude and Perplexity constantly. It drove me crazy. So I reverse engineered why. Turns out there's a whole new game being played and most founders don't even know it…
Dec 2025 · firstclick.so
- 19IB
I’ve spent the last 2.5 months building a product that runs LLM-powered code reviews on my pull requests — and I just launched it. The tool is built specifically for solo developers. You install it on your repo, trigger a scan by creating a pull request, and it leaves structured review comments using OpenAI under the hood. Funnily enough, I used the dev version of this app to review its own pull requests while building it. It helped me spot bugs, simplify structure, and keep quality high — all with minimal need for another human in the loop. Things I want to try out in the next months : -…
2025 · codii.dev
- 20ET
Hey Hacker News, For the last 2 months, I've been working on a testing agent to free developers from the endless maintenance of end-to-end tests. You just push up a PR, and our agent analyzes the code changes and automatically visits the preview to test things out like a real human! We also support describing tests in English (or even in the PR description), and we'll go through your site whenever you want via a GitHub action to test and make sure various core flows continue to work as expected. We are looking for early testers and are giving out a generous free tier! Just sign up on the…
2025 · playmatic.ai
- 21PR
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
- 22ID
Hey HN! I develop browser extensions, I suck at web design, and I've been exploring AI/LLMs. With my new found free-time since dropping work hours, I've developed a Design Copilot browser extension [0]. It does what it says on the tin - you choose a part of your website and the tool gives you instant expert design feedback - "change this font to that, add this much whitespace, use brighter colours .... etc" The tool is completely 100% free to use, its powered by bringing your own AI API Key, and the current LLM it uses is Google Gemini 1.5 Pro. I've yet to hit the free rate-limit and I…
2024 · old.reddit.com
- 23
- 24KY
Hey HN! I wanted to practice "vibe coding" and see how far and fast I can go by only prompting, without actual coding. I decided to make a simple CLI app that scrapes web docs into a single md file (I was annoyed that LLM keeps writing Tailwind 3 code for a Tailwind 4 project). In just a couple of hours, the CLI app was ready! Then iterated on arguments for another couple of hours. Result: https://github.com/vladstudio/web2llm Then I decided to go further and "productize" the CLI by making a web app for it. Another half-day, and the web app is ready!…
2025 · web2llm.dev
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