A rock-solid default for HTML5 awesome. HTML5 Boilerplate is the professional badass's base HTML/CSS/JS template for a fast, robust and future-proof site.
Cost / License
- Free
- Open Source
Platforms
- Online
Flat UI Pro is described as 'Is made on the basis of Twitter Bootstrap in a stunning flat-style, and the kit also includes a PSD version for designers. Flat UI Pro contains a huge number of basic components, icons and glyphs' and is an website. There are more than 50 alternatives to Flat UI Pro, not only websites but also apps for a variety of platforms, including Self-Hosted, Mac, Windows and Linux apps. The best Flat UI Pro alternative is Bootstrap, which is both free and Open Source. Other great sites and apps similar to Flat UI Pro are Tailwind CSS, Semantic UI, UIkit and Materialize.
A rock-solid default for HTML5 awesome. HTML5 Boilerplate is the professional badass's base HTML/CSS/JS template for a fast, robust and future-proof site.
A set of beautifully-designed, accessible components and a code distribution platform. Works with your favorite frameworks. Open source. Open code.

Front-end framework with a built-in dark mode and full customizability using CSS variables; great for building dashboards and tools.
Eva Design System is a free and open-source, customizable design system. Available for Sketch with Mobile and Web component libraries.

Spectre.css is a lightweight, responsive and modern CSS framework for faster and extensible development.
This project's goal is to be able to create a fully accessible material design styled website using React Components and Sass.

Little Widgets is a collection of beautifully designed HTML website widgets and popups. It’s coded, responsive, animated and ready to use on your website.



GroundworkCSS is a 100% free and open source responsive HTML5, CSS and JavaScript Framework.




The 960 Grid System is an effort to streamline web development workflow by providing commonly used dimensions, based on a width of 960 pixels. There are two variants: 12 and 16 columns, which can be used separately or in tandem.
960 Grid System is the most popular Windows, Mac & Linux alternative to Flat UI Pro.
Google's front-end web framework for building sites to the Material Design specification.



Phonon is a front-end framework made with mobile and desktop in mind. It offers clear and neutral components that integrate best practices and ideas coming from well-known design styles.
Phonon Framework is the most popular Android, iPhone, iPad & Android Tablet alternative to Flat UI Pro.