A CSS animation generator lets you build keyframe animations visually — defining keyframes, timing functions, transforms, and properties — and outputs clean, production-ready CSS code that you can copy directly into your project.
Writing CSS animations by hand means guessing timing values, refreshing the browser repeatedly, and debugging invisible keyframe issues. This tool shows you a real-time preview as you build, making animation development dramatically faster.
Build CSS Animations Visually
Define keyframes, set timing and easing, preview in real-time, and export clean CSS code.
CSS Animation Basics
CSS animations use two components: the @keyframes rule (defining what changes) and the animation property (defining how it plays).
Core Syntax
@keyframes slidIn {
from { transform: translateX(-100%); opacity: 0; }
to { transform: translateX(0); opacity: 1; }
}
.element {
animation: slidIn 0.5s ease-out forwards;
}Animation Property Breakdown
| Property | What It Controls | Example Values |
|---|---|---|
| animation-name | Which @keyframes to use | slideIn, fadeOut, bounce |
| animation-duration | How long one cycle takes | 0.3s, 1s, 2s |
| animation-timing-function | Speed curve (easing) | ease, linear, ease-in-out, cubic-bezier() |
| animation-delay | Wait before starting | 0s, 0.5s, 1s |
| animation-iteration-count | How many times to repeat | 1, 3, infinite |
| animation-direction | Forward, reverse, or alternate | normal, reverse, alternate |
| animation-fill-mode | State before/after animation | none, forwards, backwards, both |
animation: name duration timing-function delay iteration-count direction fill-mode. Example: animation: fadeIn 0.5s ease-out 0s 1 normal forwards;
Understanding Timing Functions (Easing)
The timing function controls the speed curve of your animation. It is the difference between mechanical-looking and natural-feeling motion:
| Easing | Behavior | Best For |
|---|---|---|
| linear | Constant speed | Progress bars, continuous rotation |
| ease | Slow start, fast middle, slow end | General purpose (default) |
| ease-in | Slow start, fast end | Elements leaving the screen |
| ease-out | Fast start, slow end | Elements entering the screen |
| ease-in-out | Slow start and end | Looping animations, toggles |
| cubic-bezier() | Custom curve | Bounce, overshoot, spring effects |
Use ease-out for entrances (elements appearing), ease-in for exits (elements disappearing), and ease-in-out for anything that loops or toggles. Never use linear for UI motion — it feels robotic.
Common Animation Patterns
These are the most frequently used animation patterns on modern websites:
1. Fade In
@keyframes fadeIn {
from { opacity: 0; }
to { opacity: 1; }
}2. Slide Up
@keyframes slideUp {
from { transform: translateY(20px); opacity: 0; }
to { transform: translateY(0); opacity: 1; }
}3. Scale (Pop In)
@keyframes popIn {
from { transform: scale(0.8); opacity: 0; }
to { transform: scale(1); opacity: 1; }
}4. Pulse
@keyframes pulse {
0%, 100% { transform: scale(1); }
50% { transform: scale(1.05); }
}5. Shake (Error)
@keyframes shake {
0%, 100% { transform: translateX(0); }
25% { transform: translateX(-5px); }
75% { transform: translateX(5px); }
}The visual generator lets you build these patterns by clicking — set the keyframe percentages, choose the transform, and see the preview instantly.
Animation Performance Tips
Poorly built animations cause jank (visible stuttering), especially on mobile devices. Follow these rules:
Animate Only Cheap Properties
| Property | Performance | GPU Accelerated |
|---|---|---|
| transform | Excellent | Yes |
| opacity | Excellent | Yes |
| filter | Good | Partial |
| width/height | Bad | No (causes layout) |
| margin/padding | Bad | No (causes layout) |
| top/left/right/bottom | Bad | No (causes layout) |
Only animate transform and opacity. These are GPU-accelerated and do not trigger layout recalculation. Moving an element? Use transform: translateX() instead of changing left/margin-left.
- Use will-change sparingly — Adding will-change: transform hints the browser to prepare, but overuse wastes GPU memory
- Prefer CSS over JavaScript — CSS animations run on the compositor thread, keeping the main thread free for user interaction
- Reduce animation on mobile — Use prefers-reduced-motion media query to disable or simplify animations for users who prefer less motion
Respecting prefers-reduced-motion
Some users have vestibular disorders or motion sensitivity. Modern browsers let users request reduced motion:
@media (prefers-reduced-motion: reduce) {
* {
animation-duration: 0.01ms !important;
transition-duration: 0.01ms !important;
}
}This disables animations for users who have enabled "Reduce motion" in their OS settings (available on Windows, macOS, iOS, and Android). Always include this in your CSS when using animations.
WCAG 2.1 Level AAA (Guideline 2.3.3) requires providing a mechanism to disable motion animation. Even at Level AA, auto-playing animations must be pausable.
How to Use the Tool (Step by Step)
- 1
Define Keyframes
Add keyframe points (0%, 50%, 100%) and set the CSS properties at each point — transform, opacity, color, etc.
- 2
Set Timing and Easing
Choose animation duration, delay, iteration count, and timing function (ease, linear, or custom cubic-bezier).
- 3
Preview in Real-Time
Watch the animation play on the preview element. Adjust keyframes until the motion looks right.
- 4
Copy CSS Code
Export the generated @keyframes rule and animation property. Paste directly into your CSS file.
Frequently Asked Questions
What is a CSS keyframe animation?+−
A @keyframes rule defines the intermediate steps in a CSS animation. You specify property values at different points (0%, 50%, 100%) and the browser interpolates between them smoothly.
What is the difference between animation and transition?+−
Transitions animate between two states (hover, focus, active). Animations can have multiple keyframes, loop, and play automatically. Use transitions for interactive state changes, animations for complex or auto-playing motion.
How do I make animations smooth?+−
Only animate transform and opacity (GPU-accelerated). Avoid animating width, height, margin, or top/left. Use ease-out for entrances, ease-in for exits. Keep duration between 200-500ms for UI animations.
What is cubic-bezier?+−
A custom timing function defined by 4 control points. cubic-bezier(0.68, -0.55, 0.27, 1.55) creates a bouncy overshoot effect. The generator lets you visually adjust the curve.
How do I stop an animation at its final state?+−
Set animation-fill-mode: forwards. Without this, the element snaps back to its original state when the animation ends.
Should I use CSS or JavaScript for animations?+−
CSS for simple transitions and keyframe animations (better performance, runs on compositor thread). JavaScript (GSAP, Framer Motion) for complex sequences, scroll-triggered, or physics-based animations.
How do I disable animations for users with motion sensitivity?+−
Use the prefers-reduced-motion media query. Set animation-duration and transition-duration to near-zero for users who have enabled reduced motion in their OS settings.
Is this CSS animation generator free and private?+−
Yes. Everything runs in your browser. No code is sent to any server.
Build CSS Animations Visually
Define keyframes, set timing and easing, preview in real-time, and export clean CSS code.
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