CSS Animation Generator

Build CSS animations without hand-writing keyframes. Set an animation name, duration, timing function, iteration behavior, and direction, then edit any number of keyframes with transform, opacity, and background color controls. A live preview box plays the animation instantly so you can tune motion with confidence.

Preset motions like Bounce, Fade In, Slide In, Pulse, Spin, and Shake help you start quickly, while the full generated CSS includes both the @keyframes block and an animation shorthand declaration. This is ideal for interface prototyping, marketing components, loading states, and motion design experimentation.

CSS animations bring interfaces to life by transitioning properties smoothly between defined states using keyframes. Each keyframe specifies the property values at a particular point in the animation timeline (0%, 25%, 50%, 75%, 100%, etc.). The browser interpolates between these keyframes to create smooth motion.

The animation shorthand property combines eight sub-properties: name, duration, timing-function, delay, iteration-count, direction, fill-mode, and play-state. The most common pattern is: animation: fadeIn 0.3s ease-out forwards. The name references your @keyframes block, the duration sets how long one cycle takes, the timing function controls the acceleration curve, and fill-mode determines whether styles apply before or after the animation runs.

Timing functions control the acceleration and deceleration of your animation. Ease (default) starts slow, speeds up, then slows down. Linear maintains constant speed. Ease-in starts slow and accelerates. Ease-out starts fast and decelerates. Ease-in-out starts slow, speeds up, then slows down. Custom cubic-bezier curves give you precise control over the timing. For natural-feeling motion, ease-out is generally preferred for entrance animations and ease-in for exit animations.

The animation-fill-mode property is often overlooked but critical for correct behavior. Forwards ensures the element retains the final keyframe styles after the animation completes — without it, the element snaps back to its original state. Backwards applies the first keyframe styles immediately, even during a delay. Both combines both behaviors.

Transform-based animations (translate, rotate, scale) are GPU-accelerated and perform significantly better than animating layout properties like width, height, top, or left. Always prefer transform and opacity for animations, as these properties do not trigger layout recalculations and can be composited on the GPU.

Performance best practices: Animate only transform and opacity when possible. Use will-change: transform on elements that will animate to hint the browser to optimize compositing. Avoid animating box-shadow (use a pseudo-element approach instead), and use contain: layout on containers with animated children to limit the scope of browser recalculations.

Common animation patterns for UI: Fade in for revealing content (opacity 0 to 1 with a slight upward translate), scale up for new elements appearing (scale 0 to 1 with ease-out), slide in for navigation drawers and modals (translate from off-screen), and pulse for drawing attention (subtle scale oscillation). Keep durations between 150ms and 500ms for UI feedback — shorter feels snappy, longer feels smooth. For decorative or marketing animations, longer durations of 1-3 seconds are appropriate.