Dev tools · alternatives · 2026

Thi.ng is a portfolio and archive website showcasing over 250 open-source projects for computational design developed since 2006. It serves as a resource for designers and developers seeking modular building blocks and… Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes. Prices are shown for the 1 we have checked on their own sites, 1 of them free or with a free tier. Thi.ng – open-source building blocks for computational design launched in 2020; newer entries below may have overtaken it.

1. 1
   21st.dev▲1,211

   I originally built this app to organize and reuse interesting React + Tailwind components I came across on Twitter, inspired by the shadcn/ui approach. Later, a friend started contributing their own components, and it got me thinking—this could grow into something bigger, like an NPM for design engineers to share and use components. Would love to hear your thoughts!

   2025 · 21st.dev · its alternatives →

2. 2
   A2UI▲250

   A safe way for AI to build UIs your app can render

   Dec 2025 · a2ui.org · its alternatives →

3. 3
   UI Sources▲418

   Curated interaction design patterns from the best apps

   2018 · screensdesign.com · its alternatives →

4. 4
   Once UI 1.5▲302

   When I started my career and built my first design system, I was beyond excited. It took a lot of iterations, learning and 6 months of work to launch it internally. In the next job, I did it again, then at the following job, again… And no matter which company I worked for, 80% of the design system was the same. I’ve decided to work full-time on the design system I’ve always wanted, and today I’m launching and open-sourcing it. You can use it to build Next.js apps faster, and I’ve designed it in a way that it’s hard to go wrong with it: you can choose any settings, and you’ll end up with a…

   Dec 2025 · once-ui.com · its alternatives →

5. 5
   UI Design Daily▲334

   1073 open-source UI designs, updated daily

   2020 · uidesigndaily.com · its alternatives →

6. 6
   UIHUT 2.0▲362

   15,000+ design & code resources

   2021 · its alternatives →

7. 7
   OpenUI▲322

   Thesys just open-sourced their generative UI rendering engine. Interesting timing given where Google a2ui and Vercel's json-render are headed. The difference worth noting: a2ui and json-render both treat JSONL as the contract between the LLM and the renderer. Thesys is betting that's the wrong primitive. Their engine uses a code-like syntax (OpenUI Lang) instead — LLM writes it, renderer executes it. The argument is that LLMs are fundamentally better at generating code than generating structured data, so you get cleaner output and ~67% fewer tokens. The broader vision seems to be a…

   Mar 2026 · openui.com · its alternatives →

8. 8
   LangUI▲131

   Open source UI components tailored for your AI projects

   2023 · langui.dev · its alternatives →

9. 9
   AI-assisted Contember Studio▲271

   From concept to web app in minutes, fine-tune in TypeScript

   2023 · contember.com · its alternatives →

10. 10
    Open-sourcing our text-to-CAD app▲179

    Hey HN! I'm Zach from Adam (https://adam.new/). We’re building an AI co-pilot for mechanical CAD software. As part of our broader research, we built a browser-based Text-to-CAD app (https://news.ycombinator.com/item?id=44182206) and are now open sourcing it. This is a React SPA with a Supabase backend. What it does: * Generates parametric 3D models from natural language descriptions, with support for both text prompts and image references * Outputs OpenSCAD code with automatically extracted parameters that surface as interactive sliders for instant dimension…

    2025 · github.com · its alternatives →

11. 11
    PATTTTERNS▲129

    Build your FREE UI Library based on real UX-UI patterns.

    2021 · patttterns.com · its alternatives →

12. 12
    Nous – Open-Source Agent Framework with Autonomous, SWE Agents, WebUI▲155

    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 · its alternatives →

13. 13
    Open-Source Alternative to OpenAI Platform, for Local Models▲93

    Hi everyone, we’re a small team, supported by Mozilla, who are working on re-imagining a UI for training, tuning and testing local LLMs. Everything is open source. If you’ve been training your own LLMs or have always wanted to, we’d love for you to play with the tool and give feedback on what the future development experience for LLM engineering could look like.

    2025 · github.com · its alternatives →

14. 14
    Live AI Design Benchmark▲81

    Hey HN, We built a different kind of AI benchmark for UI generation. Instead of static leaderboards or curated screenshots, you can watch multiple models generate the same design live, side-by-side, and decide which output is actually better. Under the hood, we call AI models from Anthropic (Opus), OpenAI (GPT), Google (Gemini), and Moonshot AI (Kimi). Each model generates a real, editable project using Tailwind CSS (not screenshots or canvas exports). You can export it for Next.js, Laravel (Blade), Symfony (Twig), WordPress, or plain HTML. What we noticed building this: * Popular benchmarks…

    Feb 2026 · shuffle.dev · its alternatives →

15. 15
    blocks.so▲61

    Open-source UI library built with React, Tailwind and shadcn

    Nov 2025 · blocks.so · its alternatives →

16. 16
    ART – a new open-source RL framework for training agents▲116

    Hey HN, I wanted to share a new project we've been working on for the last couple of months called ART (https://github.com/OpenPipe/ART). ART is a new open-source framework for training agents using reinforcement learning (RL). RL allows you to train an agent to perform better at any task whose outcome can be measured and quantified. There are many excellent projects focused on training LLMs with RL, such as GRPOTrainer (https://huggingface.co/docs/trl/main/en/grpo_trainer) and verl…

    2025 · github.com · its alternatives →

17. 17
    Hamilton's UI – observability, lineage, and catalog for data pipelines▲40

    Hey HN – Stefan and Elijah here from DAGWorks (http://dagworks.io/, YC W23). If you don’t remember us from our previous HN launch (https://news.ycombinator.com/item?id=35056903), we’re the authors of Hamilton (https://github.com/dagworks-inc/hamilton), an open-source library for building self-documenting, modular dataflows in python that works for data, ML, LLM pipelines, & even web-workflows. We’ve been developing this UI for a while and we’re excited to say we open-sourced it! It comes out of the box with the following capabilities, and…

    2024 · github.com · its alternatives →

18. 18
    RXWeb▲64

    Open-source architecture for web apps in Angular & .Net Core

    2020 · rxweb.io · its alternatives →

19. 19
    Gotui – a modern Go terminal dashboard library▲49

    I’ve been working on gotui, a modern fork of the unmaintained termui, rebuilt on top of tcell for TrueColor, mouse support, and proper resize handling. It keeps the simple termui-style API, but adds a bunch of new widgets (charts, gauges, world map, etc.), nicer visuals (collapsed borders, rounded corners), and input components for building real dashboards and tools. Under the hood the renderer’s been reworked for much better performance, and I’d love feedback on what’s missing for you to use it in production.

    Dec 2025 · github.com · its alternatives →

20. 20
    AgnosticUI a React, Vue 3, Svelte, and Angular UI Library▲24

    I’ve spent the last few years building AgnosticUI. It started as a CSS-first monorepo with logic manually duplicated across framework packages. It turned into a maintenance nightmare. I recently completed a total rewrite in Lit to align with web standards and unify the core. One major architectural shift was moving to a "Source-First" model. Instead of a black box in node_modules, the UI source lives in your local project workspace. This makes the components fully visible to LLMs, preventing the hallucinations common when AI tries to guess at hidden library APIs. I wrote a technical…

    2022 · agnosticui.com · its alternatives →

21. 21
    Open-source AI web parser lib & TUI▲17

    Hey HN! I'm open-sourcing a little weekend side project. It's a terminal UI that generates parsers for webpages using AI, and a library that runs these parsers while you browse (it connects to Chrome over CDP). You can parse Twitter, LinkedIn, and HN posts and they get saved to a DuckDB database, so you can query them later. Contributions welcome! I wrote a bit more about it here: https://0thernet.substack.com/p/memo-2-selectron

    2025 · github.com · its alternatives →

22. 22
    Output.ai - OSS framework we extracted from 500+ production AI agents▲40

    Open-source TypeScript framework for AI dev: prompts, evals, tracing, cost tracking, security, and durable execution. Built for Claude Code.

    Apr 2026 · output.ai · its alternatives →

23. 23
    I built an open-source AI data layer that connects any LLM to any datafree▲18

    Excited to share a project I’ve been building for months! Would love to receive honest feedback :) My motivation: AI is clearly going to be the interface for data. But earlier attempts (text-to-SQL, etc.) fell short — they treated it like magic. The space has matured: teams now realize that AI + data needs structure, context, and rules. So I built a product to help teams deliver “chat with data” solutions fast with full control and observability (agent tracing, quality scores, etc) — am I wrong? The product allows you to connect any LLM to any data source with centralized context…

    2025 · github.com · its alternatives →

24. 24
    We made a platform that allows you to build UI kits in days not months▲20

    Hey devs :) With 15+ years of UI kit building & design systems, my team is launching a platform that allows developers to build consistent & fully functional UI kits / web projects in days, instead of months. Giving you best practices with the most advanced system design/system design for reusing UI components, combined with access to 500+ open-source components that you can build anything with. Yes it’s open source tech with no vendor lock. Which means you can export any part of your UI kit / project at anytime. Our goal isn’t to enhance your tech stack, not to lock you in.…

    2024 · symbolsapp.framer.website · its 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 →