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How do I create CSS keyframe animations online?

Choose from animation presets (fade, slide, bounce, rotate, pulse, and more) or build custom keyframe animations visually. Set timing function, duration, delay, iteration count, and direction. See a live preview and copy the production-ready @keyframes CSS. Everything runs in your browser.

Fade in from bottom
Input
Name: fadeInUp
Duration: 0.5s
Timing: ease-out
From: opacity 0, translateY 20px
To: opacity 1, translateY 0
Output
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}
.element {
  animation: fadeInUp 0.5s ease-out;
}
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CSS Animation Generator

Build CSS keyframe animations visually. Configure timing, add keyframes, preview live, then copy production-ready CSS.

Preview

Animation Properties

Keyframes (2)

0%25%50%75%100%
%
px
px
deg
0%
deg
deg

CSS Output

@keyframes myAnimation {
  0% {
    opacity: 0;
  }
  100% {
    transform: none;
  }
}

.animated-element {
  animation: myAnimation 0.6s ease 0s 1 normal both;
}

Presets

About CSS Animations

CSS animations allow elements to transition between styles over time using @keyframes rules and the animation shorthand property.

@keyframes define the animation steps. Each keyframe specifies CSS properties at a given percentage (0% = start, 100% = end).

Duration controls how long one cycle takes. Delay sets time before the animation starts.

Timing function controls acceleration: ease starts slow, speeds up, then slows; linear is constant speed.

Fill mode determines styles before/after animation: forwards keeps the final state, both applies in both directions.

Direction: alternate reverses every other cycle, creating smooth back-and-forth effects. Use with infinite iteration count for looping animations.

Performance tip: animate transform and opacity for best performance — they run on the GPU compositor and don't trigger layout recalculations.

Tips & Best Practices

Pro Tip

Animate only transform and opacity for 60fps performance

Animating width, height, top, left, margin, or padding triggers layout recalculation on every frame. Animating transform (translate, scale, rotate) and opacity runs on the GPU compositor thread, bypassing the main thread entirely. This is the difference between janky 15fps and smooth 60fps animations.

Common Pitfall

will-change creates a new stacking context and compositor layer

will-change: transform promotes an element to its own GPU layer, which uses memory. Apply it to 2-5 elements max, not broadly. Overuse causes excessive memory consumption and can actually decrease performance. Only apply will-change just before the animation starts and remove it after.

Real-World Example

Use @media (prefers-reduced-motion) to respect user preferences

@media (prefers-reduced-motion: reduce) { *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; } } Users with vestibular disorders enable reduced motion in their OS settings. Ignoring this preference is an accessibility violation.

Security Note

Animations can be used for timing attacks

CSS animations fire animationend events that reveal timing information. An attacker could measure animation completion time to infer CSS selector matches (history sniffing via :visited selectors was patched, but novel timing channels emerge periodically). Keep security-sensitive UI state independent of CSS animations.

Frequently Asked Questions

How do I create a CSS keyframe animation?
Define animation steps using the @keyframes rule with percentage values from 0% to 100%, then apply the animation to an element using the animation shorthand property. DevBolt's CSS Animation Generator provides a visual timeline editor where you add keyframes, set properties at each point, and preview the animation in real time. The tool generates both the @keyframes rule and the animation property, which you copy directly into your CSS. Adjust duration, timing function, delay, and iteration count visually. Common animations like fade-in, slide, bounce, and spin are included as presets to get started quickly.
What is the difference between CSS transitions and CSS animations?
CSS transitions animate between two states when a property changes, typically triggered by user interaction like :hover or :focus. CSS animations use @keyframes to define multi-step sequences that can run automatically on page load, loop indefinitely, and animate through multiple intermediate states. Transitions require a trigger event and only animate between start and end states. Animations offer iteration count, direction (normal, reverse, alternate), fill-mode to persist final state, and play-state to pause mid-animation. Use transitions for interactive feedback like button hovers. Use keyframe animations for loading spinners, entrance effects, and sequences without user interaction.
What does animation-fill-mode do in CSS?
The animation-fill-mode property controls how styles are applied before the animation starts and after it ends. none (default) applies no styles outside the active animation period. forwards retains the styles from the last keyframe after the animation completes, preventing the element from snapping back. backwards applies the first keyframe styles during any delay period before the animation begins. both combines forwards and backwards behavior. This property is essential for entrance animations: if you animate opacity from 0 to 1, without fill-mode forwards the element reverts to invisible after the animation ends.

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