web
A chart grammar you don't have to outgrow.
A typed, tree-shakable chart grammar for SVG and Canvas. Compose marks, views, scales, transforms, interactions, and motion with compact primitives or D3-compatible inputs.
textmode.js is a lightweight creative coding library for creating real-time ASCII art on the web.
Interactive SVG maps toolkit for React 19 and Vue 3. Choropleths, markers, routes, bubble and zoomable maps with components powered by d3.js.
Preview how pages look when shared, on every major platform.
OGee is a Chromium extension that shows how the current page’s Open Graph link card will look when it is shared. Open the popup on any page to see the real thumbnail, title, description, and domain each platform would display, side by side, in both light and dark themes.
Automated PWA health check tool to make sure your PWA looks, feels, and behaves like a real app.
Audit shadcn apps for UI fundamentals.
Deterministic UI audits for shadcn apps
shadscan statically analyzes your React shadcn components for accessibility, state, and composition regressions — the same result on every run, built for your terminal and your CI.
WebGPU LLM Inference Engine. The open-source Three.js-based modern LLM Engine that runs in your browser via WebGPU compute.
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High-Performance In-Browser LLM Inference Engine.
WebLLM is a high-performance in-browser LLM inference engine that brings language model inference directly onto web browsers with hardware acceleration. Everything runs inside the browser with no server support and is accelerated with WebGPU.
Offline-first SQL sync with Typescript and Rust cores.
Syncular keeps an SQLite database on each client and synchronizes it through a server-owned commit log. Apps read from local SQLite and continue to work offline. A write updates local state immediately, enters an outbox, and is checked by the server when it syncs.
A minimal CSS toolkit. The standards-first, full-featured CSS library for the modern web.
Utilities, elements, blocks, and templates. Highly configurable. Endlessly themeable. Zero JavaScript. Works with your favorite framework or straight-up HTML.
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SSR islands for SvelteKit.
Your pages are HTML. Nothing hydrates until you say so. Mark a component and it wakes: on load, on scroll, on whatever cue you pick. Everything else stays static. No Kit client to boot, so you ship JavaScript only for what you marked.
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Modern React Component Library.
Build beautifulpiece by piece.
A dark-mode React component library. 19 production-ready components built with TypeScript, Tailwind CSS, and Framer Motion.
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Able Player is a fully accessible cross-browser HTML5 media player.
The Visual JSON Editor for Humans.
The Visual JSON Editor. Schema-aware, embeddable, extensible.
Compiler-First Reactive UI. Write JavaScript. Get reactivity for free.
A compiler-first UI framework that turns ordinary classes and functions into surgical DOM updates. No virtual DOM. No hooks. No signals. Just your code — wired at build time.
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A library for building dynamic webapps, using Js_of_ocaml.
Bonsai is a UI library for building performant, reactive web applications in OCaml, partly inspired by Elm. It is used to build almost all web applications inside Jane Street, everything from the corporate directory to tools that monitor and interact with our trading systems. A simple Bonsai component with a little interactivity looks like this:
A hook that registers a WebMCP tool with the browser and ties its lifecycle to a React component.
WebMCP lets a page expose JavaScript functions as "tools" that an AI agent (browser-built-in, iframe-hosted, or extension) can discover and call. The site author can expose functionality, and the agent uses this instead of scraping the DOM, a11y tree, or using screenshots.
📈 A small, fast chart for time series, lines, areas, ohlc & bars.
uPlot is a fast, memory-efficient Canvas 2D-based chart for plotting time series, lines, areas, ohlc & bars. From a cold start it can create an interactive chart containing 166,650 data points in 25ms, scaling linearly at ~100,000 pts/ms afterwards. In addition to fast initial render, the zooming and cursor performance is by far the best of any similar charting lib; at ~50 KB, it's likely the smallest and fastest time series plotter that doesn't make use of context-limited WebGL shaders or WASM, both of which have much higher startup cost and code size.
A high-performance document search engine built in Rust with WebAssembly support.
A high-performance document search engine built in Rust with WebAssembly support. Combines full-text search using FST (Finite State Transducers) with FSST compression for efficient storage and fast fuzzy matching capabilities.
React’s programming model, compiled. Octane is an incredibly efficient React replacement UI library with improved developer ergonomics.
The successor to Inferno, carrying its performance-first goal forward: React’s hooks, Suspense and actions, compiled ahead of time. No virtual DOM. No rules of hooks. No hand-maintained dependency arrays — the compiler works out what your code captures for you.
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TypeScript-to-Native Compiler.
Zero-runtime TypeScript. scriptc compiles ordinary TypeScript into small, fast native executables — no Node, no V8, no JavaScript engine in the binary.
No changes to your code. No annotations, no dialect — the same TypeScript you run on Node, type-checked by the real TypeScript compiler and compiled to native. What compiles behaves byte-for-byte like Node.
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The Web Without JavaScript. A programming language that compiles to WebAssembly, built for the next era of web development.
Nectar compiles to WebAssembly. One language, one binary, zero dependencies. Your entire app — logic, state, rendering — runs in WASM. JavaScript is reduced to a 10 KB syscall layer.
Topcoat is a modular, batteries-included Rust framework for building fullstack apps. It prioritizes simplicity and productivity.
The web, wired into your local agent.
wigolo is a local-first server that hands any AI agent the whole web — search, fetch, crawl, extract, cache, and research. In your editor over MCP, in your framework through an SDK, or in your self-hosted stack over REST. No API keys. No cloud. No metered bill.
The VanillaJS Agent UI Library. Create agentic front-end experiences for the web in VanillaJS™️. Lightweight, extensible, and WebMCP-native.
Persona helps you create agentic front-end experiences for the web, in pure JS. Lightweight, extensible, and WebMCP-native.
Compile Zod schemas into zero-overhead validation functions at build time.
Keep your existing Zod schemas. Get 2-75x faster validation. No code changes required.
A website, frozen as a shadow. Shadow any website for offline viewing, with the JavaScript stripped out .
kage renders every page in headless Chrome, snapshots the final DOM, removes every script and event handler, and downloads and rewrites the CSS, images, and fonts. The result looks like the live site but runs no code: a plain folder of .html files you can open straight from disk.
Map of tools that describe compat on the web.
Each tool page on webcompat.dev embeds a <tool-graph> custom element that renders a mini force-directed graph with the tool in the centre and its direct connections around it. The component can also be embedded on external sites.
A library that unifies the APIs of IndexedDB, localStorage and other storage into a consistent API.
modern storage toolkit that keeps localForage compatibility while using async/await, TypeScript, and zero legacy baggage.
A command-line tool for looking up web platform features. Search by keyword, check Baseline status, find MDN docs, specs, browser bugs, survey results, and more, from your terminal.
This is an experimental MCP server that provides access to MDN's search, documentation, and browser compatibility data.
Our goal is to give LLMs and coding agents a reliable and up-to-date source of web platform documentation - so developers can get accurate information instead of potentially outdated content their LLMs were trained on.
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Inject web platform expertise, best practices, and modern API patterns directly into your AI coding agents.
Modern Web Guidance is an agent skill (aka SKILL.md) with a CLI that helps coding agents build better web applications using modern, high-performance, accessible, and secure APIs instead of legacy workarounds.
TypeScript Frontend Framework Built on Effect-TS. Built on Effect. Architected like Elm. Written in TypeScript.
Foldkit is for developers who want to build their product with confidence instead of fighting their architecture. If you want a single pattern that scales from a counter to a multiplayer game without complexity creep, this is it.
Terminal Emulator for the Web.
wterm ("dub-term") renders to the DOM — native text selection, copy/paste, find, and accessibility come for free. The core is written in Zig and compiled to WASM for near-native performance.
Zero-dependency spreadsheet engine — XLSX, CSV, ODS, JSON, NDJSON, XML.
Schema validation, streaming, round-trip preservation. Pure TypeScript, works everywhere.
MDF (Markdown First) — open web architecture proposal for native markdown serving, agent-readable content, and price-as-access-policy.
A proposal for a web content architecture where markdown is the source of truth, agents are first-class citizens, and access policy is expressed through price.
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What a good website does.
A platform-agnostic specification of the technical features every decent website should have — from <title> to /.well-known/security.txt, from WCAG contrast to llms.txt. Written for humans and agents.
🍫 Tastier cookies, local, session, and db storage in a tiny package. Includes subscribe() events for changes.
DirPlayer is a Shockwave Player emulator written in Rust that aims to make playing old browser games possible on modern browsers.
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Updo is a command-line tool for monitoring website uptime and performance. It provides real-time metrics on website status, response time, SSL certificate expiry, and more, with alert notifications.
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Effortlessly Save and Preserve Web Pages. Web Extension for saving a faithful copy of a complete web page in a single HTML file.
SingleFile is a browser extension that allows you to save an entire web page, including all its resources (e.g., images, stylesheets, fonts, frames, etc.), as a single HTML file with just one click.
The saved page can be displayed offline in any browser without needing to install any extension. Ideal for researchers, students, and professionals needing reliable offline copies of web pages, or for anyone wanting to keep a record of their favorite web content.
SingleFile is available for Chrome, Edge, Firefox, and Safari. It is free and open source.
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Open Source Video Player.
open source media player framework for Web and React. Modern, modular, and composable media player framework for Web and React.
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Terminal apps that run anywhere - even the browser!
Build terminal apps that run in the browser (and the terminal) with React. The Gridland website is built with Gridland.
Gridland is built on the OpenTUI rendering engine.
Property-based testing for web UIs, autonomously exploring and validating correctness properties, finding harder bugs earlier.
Runs in your local developer environment, in CI, and inside Antithesis.
Automate your web typography workflow with this Composer dev-tool. 🚀
Converts TTF fonts to optimized WOFF2 subsets using Python FontTools. Works with Laravel, Symfony, and vanilla PHP projects.
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Converts PNG/JPG images to AVIF, WebP and JPG in multiple sizes. Automate your web image workflow with this Composer dev-tool. 🚀 .
Works with Laravel, Symfony, and vanilla PHP projects.
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Named .localhost URLs for Development. Replace port numbers with stable, named local URLs. For humans and agents.
Portless replaces port numbers with stable, named .localhost URLs for local development. For humans and agents.
End-to-End UI Testing for Mobile and Web.
Maestro makes UI testing dead simple. Write your first test in under 5 minutes. Maestro is an open-source framework that makes UI and end-to-end testing for Android, iOS, and web apps simple and fast. Write your first test in under five minutes using YAML flows and run them on any emulator, simulator, or browser.
A unified TypeScript SDK for building chat bots across Slack, Microsoft Teams, Google Chat, Discord, Telegram, GitHub, Linear, and WhatsApp. Write your bot logic once, deploy everywhere.
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Optimising Web Delivery.
Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. It reduces bandwidth and improves response times by caching and reusing frequently-requested web pages. Squid has extensive access controls and makes a great server accelerator. It runs on most available operating systems, including Windows and is licensed under the GNU GPL.
Looking for inspiration? Browse our curated collection of HTML UI components ready to drop into your next project.
In December 1990, an application called WorldWideWeb was developed on a NeXT machine at The European Organization for Nuclear Research (known as CERN) just outside of Geneva. This program – WorldWideWeb — is the antecedent of most of what we consider or know of as "the web" today.
In February 2019, in celebration of the thirtieth anniversary of the development of WorldWideWeb, a group of developers and designers convened at CERN to rebuild the original browser within a contemporary browser, allowing users around the world to experience the rather humble origins of this transformative technology.
Arduino (8-bit AVR) simulator, written in JavaScript and runs in the browser / Node.js
Super-configurable and well-tested web page minifier (enhanced successor of HTML Minifier).
The WebMCP API enables web applications to provide JavaScript-based tools to AI agents.
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Spring Boot helps you to create Spring-powered, production-grade applications and services with absolute minimum fuss.
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Stable. Lightweight. Instantly Familiar.
A lightweight, stable, instantly familiar free open-source content management system. Forked from WordPress without the block editor (Gutenberg).
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A Tool to Redirect News, Search, Widgets, Weather and More to Your Default Browser.
This tool filters and passes the command line arguments of Microsoft Edge processes into your default browser instead of hooking into the microsoft-edge: handler, this should provide resiliency against future changes. Additionally, an Image File Execution Options mode is available to operate similarly to the Old EdgeDeflector. Additional modes are planned for future versions.
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holistic Visual Regression Testing cloud. Open source alternative to Percy, Chromatic, Applitools.
Lost Pixel is an open-source visual regression testing tool. Run visual regression tests on your Storybook and Ladle stories and your application pages.