AI · alternatives · 2026
24 alternatives to I made a JSFiddle-style playground to test and share prompts fast
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…
This is a browser-based prompt testing playground designed for AI developers and teams. It allows users to test and share prompts with variables and Jinja2 templates across different models without requiring signup… Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes.
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Hey, Jared Palmer (creator of this playground) here. Really excited to ship this. I’ve been building this over the past few weeks to compare LLMs from different providers like OpenAI, Anthropic, Cohere, etc. At Vercel, I manage our Frameworks division (including Next.js, Svelte, and Turbo) and wanted to also dogfood some of the latest features in a slightly larger application. This playground takes a lot of inspiration from https://nat.dev and is built on Tailwind, ui.shadcn.com, and some upcoming Vercel products we’re announcing soon. We’re going to continue adding models to…
2023 · play.vercel.ai · its alternatives →
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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 · its alternatives →
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Playground▲198We build AI agents to find vulnerabilities in other AI agents. The playground started as an internal tool that we used to test our own offensive agent Nyx. But we realised that hacking an AI is about have as wide a distribution of attacks as possible, especially those which aren't in the distribution of the models. So we are launching playground as a platform to crowdsource agent jailbreaks. And although hacking AI is super fun and we are sure people will do it for free, we want to reward those who help us push forward the offensive frontier of AI. So we are committing $100K in prizes over…
Jul 2026 · playground.fabraix.com · its alternatives →
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I recently dug up an old project in an attempt to improve on it. It's a code sandbox for playing around with HTMX in the browser, that runs a mock server within the sandbox iframe. The server "framework" is loosely based on Django, so if you're familiar with Django, you'll immediately understand what's going on. I recommend clicking through the examples. Github repo: https://github.com/lassebomh/htmx-playground Probably my favorite part is the lack of HTMX specific code. It's designed to mimic the client and server, but really nothing else. In principle, this means that…
2024 · lassebomh.github.io · its alternatives →
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PrompTessor▲125After countless hours of solo coding, designing, and iterating, I’m both excited and nervous to share my first-ever product: PrompTessor — now live. As someone who constantly experiments with AI tools like ChatGPT and Midjourney, I often found myself stuck in a loop of trial-and-error. The issue wasn’t always the AI — it was often the prompt itself. That observation became the starting point for PrompTessor. This tool doesn’t just optimize your prompt — it analyzes it. It gives you: - A prompt score - A breakdown of strengths and weaknesses - A fully optimized version of your prompt - And…
2025 · promptessor.com · its alternatives →
- 6TI
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 · its alternatives →
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Test LLM prompts & models side-by-side against many inputs
2024 · its alternatives →
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Preflight▲77Hey HN, I’m a product designer on a payments team. Every time we were close to shipping a feature, we’d run a bug bash in a giant Google doc or spreadsheet: copy the spec in, write the test cases, ask people to mark Pass/Fail, paste screenshots, then manually turn everything into Jira tickets. It worked, but it always felt a bit painful. Instead of another heavy test management tool, I wanted something that feels closer to the tools we actually like using. More Linear/Notion, less old-school QA. With Preflight, you paste your product requirements and Figma link and get an initial…
Dec 2025 · preflightqa.xyz · its alternatives →
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Hi HN, I built Prompt Builder (https://www.promptbuilder.space/) because I was frustrated managing complex AI prompts in plain text boxes. The core idea: instead of one giant textarea, you compose prompts from draggable, reorderable blocks. Each block can have its own XML/custom tags, visibility toggles (so you can A/B test sections), and duplicates. Key technical details: - Live compiled preview: the right pane shows the exact string being sent, updating as you drag/toggle blocks - Dynamic variables: define {{var_name}} once, use across blocks, change in one…
Aug 2026 · promptbuilder.space · its alternatives →
- 10IB
Hey all! I wanted to share this project I've been working on that can maybe help you or your developer friends out. I built a RAG system for our product a while back and didn't realize how easy they were to get started. So I put together my learnings into this online course. It's not quite ready but if you sign up and mention HackerNews, I can get you early access. I'm looking to get feedback on the following: (1) materials — is it engaging & did you learn something? (2) UI/UX of the platform — did you have any issues that prevented you from starting or finishing the tutorial? (3)…
2024 · takehomes.com · its alternatives →
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Experiment with, and evaluate, prompts and LLMs
2023 · its alternatives →
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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 · its alternatives →
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Knit was created to solve pains of other LLM playgrounds. Some of the highlights: - Smart prompt builder, create prompt with simple requirement and few shot learning, fast and effortlessly. - Function call simulation, visualize the function callings and you can also setup a mocked value to return. - Support OpenAI/Anthropic/Azure models. - Manage prompts with projects and members. - And so much more! I have been developing Knit by myself for over 4 months now, and am looking for ways to improve it. Any feedback is appreciated.
2023 · promptknit.com · its alternatives →
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Hi HN! I'm Matt, founder of Frontend Mentor (https://www.frontendmentor.io). We provide front-end and full-stack coding challenges with professional Figma designs, enabling developers to build real projects and grow their skills. The problem: AI coding tools are great, but they can work against you when you're learning. Ask Copilot or Cursor to help with a beginner project, and they'll happily write the whole thing for you. You ship the project, but you didn't really learn anything. What we did: We added AGENTS.md (and CLAUDE.md) files to every challenge's starter code. These files…
2018 · frontendmentor.io · its alternatives →
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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 · its alternatives →
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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 · its alternatives →
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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 · its alternatives →
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Edit, share and run prompt templates
Nov 2025 · stickyprompts.com · its alternatives →
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I’m the creator of Spring AI Playground, a self-hosted web UI built on Spring AI—designed to make testing and experimenting with AI tools more straightforward for Java developers. What it is Runs locally, lets you experiment with: • LLM providers (Ollama is the default, but you can switch to OpenAI, Anthropic, Microsoft, Google, and more.). • RAG workflows: upload documents, chunk, embed, search with scoring, and filter metadata. • A visual MCP (Model Context Protocol, a spec for connecting models to external tools) Playground to set up tool integrations (HTTP, STDIO, SSE), inspect tool…
2025 · github.com · its alternatives →
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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 · its alternatives →
- 21AT
Hey HN! While writing prompts for a few projects recently, a couple of friends and I realised that writing prompts today is like writing code in a txt file - it sucks and there is no tooling to help you. So we decided to hack on a tool to help you fix this - https://optimist.varied.ai/ It is literally a hack rn but we already find it useful for writing prompts. That said we'd love to talk to folks who are writing serious prompts everyday and see how the product can be better. Also the only reason the waitlist is there, is running this is super expensive like $100/day for…
2023 · optimist.varied.ai · its alternatives →
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Hi HN! Here's a local-only stack I built over the weekend - hope it can be useful for you! I have been building a lot of AI apps - https://github.com/a16z-infra/ai-town https://github.com/a16z-infra/companion-app ... And there were definitely times I spent way too much $$ before deploying the app to production. So I was looking for a "local only" stack and found a few tools that worked well together. I used the following set of tools but may add more options later: - Inference: Ollama - VectorDB: Supabase pg-vector - LLM orchestration: langchain -…
2023 · github.com · its alternatives →
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Build perfect AI prompts for any model
Jun 2026 · json-prompt-engine-frontend.vercel.app · its alternatives →
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Chainix▲12Hey everyone! I built this because I was tired of manually handling customer support for my web app and couldn't get an AI system to handle requests reliably. I tried different AI tools to help with support tickets, but when they handled requests incorrectly, it was impossible to determine why, and even harder to figure out what I needed to change to improve the system. I wanted to break down my logic of how the AI should think through the problem step-by-step, but everything had to be crammed into one prompt. Without the volume of clean training data needed for fine-tuning, I was stuck with…
2025 · chainix.ai · its alternatives →
Also compare
- AI Playground by Vercel Labs alternatives
- Why write code if the LLM can just do the thing? (web app experiment) alternatives
- Playground alternatives
- I made a HTMX Playground 100% in the browser alternatives
- PrompTessor alternatives
- Tips.io – A Tailwind playground with AI, page management, and theming 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 →