Open Source HTML/XHTML Software

HTML Inspector is a browser-based JavaScript code quality tool for checking markup against customizable rules. It was designed to sit between strict W3C validation and having no markup standards at all. The tool can detect questionable HTML patterns, enforce team conventions, and help developers catch structural problems before they become harder to maintain. Its rules are opinionated by default but can be customized or extended to match a team’s own standards. HTML Inspector runs directly in the browser, which makes it useful for inspecting live pages during development. Although the project is archived, it remains a clear example of configurable client-side markup auditing.

hyperHTML is a lightweight JavaScript rendering library built as a fast alternative to virtual DOM frameworks. It updates the native DOM directly and uses tagged template literals to combine markup with dynamic values. Developers can bind a renderer to an existing element and refresh only the interpolated parts when data changes. The library works with standard DOM nodes, plain JavaScript data structures, custom elements, and object-based style values. It is available for ESM, CommonJS, bundlers, and CDN use, while retaining broad legacy browser support. The project is now in maintenance mode, making it best suited to established applications that value its compact, battle-tested approach.

CoreUI Admin Panel is not another blend of 3rd parties free components and libraries. It's the only Open Source Bootstrap Admin Dashboard Template built on the enterprise-grade hand-crafted UI Components Library created and backed by professionals. CoreUI and CoreUI PRO are delivered with fully-featured, and ready-to-use admin panel templates for your application. Save thousands of development hours by using ready-made, reusable, and commonly used widgets and UI components. Moreover, CoreUI Bootstrap Admin Template is delivered with a ready-to-use environment, so you don't have to waste time configuring the project. All build scripts and tools are ready to use out of the box. With CoreUI Template you can start a new project in a minute!

Lexbor is the development of a web browser engine available as a software library; it ships with a free license and has no extra dependencies. For us, speed is an absolute must-have. In our development process, we focus on fastest parsing techniques for HTML, CSS, and fonts, fastest data processing methods, and fastest ways to serve content to end users. Whether you are building a backend that handles millions of HTML documents or a UI-heavy user app, your software’s response rate always matters to users and developers alike. Lexbor’s code is optimized for ease of access in end-user applications and across programming languages. You can effortlessly wrap all the capabilities of the library in, say, Python to power your end-user or backend applications in a new environment. In other words, lexbor offers a feature-rich core that developers can build upon as they see fit.

Backed by open-source code and written in Sass by the Canonical Web Team. Vanilla contains a responsive CSS grid, basic style for HTML elements and a selection of key useful patterns and utility classes that you can extend. Designed to be composable, you can include the whole framework to avail of all styles or you can use only what you need for your project. Anyone can contribute to Vanilla, improve it and extend it. All the code is available on GitHub and is licensed under LGPLv3 by Canonical.

Marx is a CSS stylesheet to be used in any project (namely small ones). If you don't need the weight of heavy frameworks or you would just like to make an edible website quickly, Marx is perfect for you. It can be used out of the minified box but it can also be customized and styled through the use of HTML classes. Built atop of Sanitize.css, meaning all browsers render consistently. Responsive and mobile-friendly. Clean, beautiful typography. Forms, tables, buttons and navigation. Zero classes, so it already works with your HTML. Drop-dead gorgeous.

Highly customizability, full TypeScript, performance pretty good. This library is using base on vue 3.0 with using composition api, and design and code components in the traditional way by Vue possible, fully TypeScript. Almost all the default value of props for each component can be quickly modified by configuration, for easy customization. And, the writing of component codes pays great attention to lowering the threshold of source code reading, and the style of code is as close to the usual business code habits as possible to avoid dazzling encapsulation. There are currently 70+ components, many you see everywhere are here and are better, and a few may bright your eyes.

Developed by the Web Technology Group at Appalachian State University, phpWebSite provides a complete web site content management system ( CMS ). All client output is XHTML 1.0 and meets the W3C's Web Accessibility Initiative requirements.

Supercharged Blade Components. This package provides an easy way to render custom HTML components in your Blade views.

Dominate is a Python library for creating and manipulating HTML documents using an elegant DOM API. It allows you to write HTML pages in pure Python very concisely, which eliminates the need to learn another template language, and lets you take advantage of the more powerful features of Python. Dominate can also use keyword arguments to append attributes onto your tags. Most of the attributes are a direct copy from the HTML spec with a few variations. Through the use of the += operator and the .add() method you can easily create more advanced structures. By default, render() tries to make all output human readable, with one HTML element per line and two spaces of indentation.

HEAD is a simple educational guide to HTML <head> elements and metadata. It explains which elements can appear inside the document head and why they matter for browsers, search engines, social platforms, bots, icons, feeds, and mobile presentation. The repository works as a practical reference for developers who want a better default head section for websites. It includes examples for character encoding, viewport settings, titles, descriptions, canonical URLs, favicons, social sharing metadata, app behavior, and other document-level concerns. The project is not a framework or package, but a curated documentation resource. It is especially useful for front-end developers, students, and site owners who want to understand the often-overlooked metadata layer of web pages.