Animate.css is a lightweight, plug-and-play CSS animation library that provides a large collection of prebuilt animations which can be applied to HTML elements using simple class names. It is designed to make it easy for developers to add motion effects to websites without writing custom keyframes or JavaScript animation logic.

The library works by defining a set of reusable CSS @keyframes animations and utility classes. Developers simply apply class names such as animate__animated and a specific animation type (for example bounce, fade, or slide effects) to trigger animations on elements. This makes it especially useful for quick UI enhancements, landing pages, and attention-grabbing interface components.

Animate.css is framework-agnostic and works in any environment that supports CSS, including plain HTML, React, Vue, and other frontend frameworks. It also supports configuration through CSS variables and utility modifiers for animation duration, delay, and repetition.

The library is optimized for simplicity and performance, relying entirely on CSS so it avoids JavaScript runtime overhead. It is widely used in combination with frontend frameworks and design systems to quickly add motion design without complex tooling.

Key features include:

• Ready-to-use CSS animation classes for common effects
• Cross-browser compatible keyframe animations
• Simple class-based usage with no JavaScript required
• Support for delays, speed control, and repetition via utility classes
• Lightweight, dependency-free implementation
• Works with any frontend framework or static HTML

Common use cases include:

• Adding entrance and exit animations to UI components
• Enhancing landing pages with motion effects
• Highlighting interactive elements
• Improving user experience with subtle transitions
• Quickly prototyping animated interfaces

Animate.css is an open-source project originally created by Daniel Eden and maintained by contributors in the web development community.