Compass vs Less vs Sass: What are the differences?

1. Syntax: One key difference between Compass, Less, and Sass is the syntax they use. Compass uses Sassy CSS, an extension of CSS3 that adds nested rules, variables, imports, and mixins. Less and Sass, on the other hand, have similar syntax with the use of variables, nesting, and mixins, but they differ in some advanced features and compilation methods.

2. Preprocessor Language: Compass is based on Sass, which is written in Ruby, whereas Less is written in JavaScript. Sass has two syntax options, the older, more strict indented syntax (Sass) and the newer, more CSS-like syntax (SCSS). Less, however, has a similar syntax to SCSS, allowing for easier transition for CSS developers.

3. Feature Set: Compass provides a set of built-in mixins and functions that can be used to streamline web development tasks like creating gradients, vendor prefixes, and more, making it a powerful choice for front-end development. Less and Sass also offer mixins and functions, but these need to be defined or imported separately, providing flexibility but requiring more setup.

4. Frameworks: Compass is a framework on its own, providing additional tools and libraries for web development. Less and Sass, however, are primarily preprocessors that can be extended with frameworks like Bootstrap or Foundation, allowing users to choose the level of abstraction and customization they need.

5. Community and Support: Compass has a dedicated community of users and contributors, but its popularity has decreased in recent years, leading to less active development and support. Less and Sass, being more widely used in the industry, have larger and more active communities with frequent updates and support from developers around the world.

6. Browser Compatibility: Compass-generated CSS may sometimes have browser compatibility issues due to the use of cutting-edge features and mixins. Less and Sass, being more widely adopted and tested, tend to have better browser compatibility out of the box, making them suitable for a wider range of projects.

In Summary, the key differences between Compass, Less, and Sass lie in their syntax, preprocessor language, feature sets, frameworks, community and support, and browser compatibility.