Gsap performance

GSAP Performance

When to Use This Skill

Apply when optimizing GSAP animations for smooth 60fps, reducing layout/paint cost, or when the user asks about performance, jank, or best practices for fast animations.

Related skills: motion-performance-qa, animation-jank-qa, animation-tool-router, and reduced-motion-design.

Prefer Transform and Opacity

Animating transform (x, y, scaleX, scaleY, rotation, rotationX, rotationY, skewX, skewY) and opacity keeps work on the compositor and avoids layout and most paint. Avoid animating layout-heavy properties when a transform can achieve the same effect.

• Prefer: x, y, scale, rotation, opacity.
• Avoid when possible: width, height, top, left, margin, padding because they trigger layout and can cause jank.

GSAP's x and y use transforms by default; use them instead of left/top for movement.

will-change

Use will-change selectively on elements that will animate soon. It hints the browser to prepare for animation work, but overusing it can increase memory pressure.

will-change: transform;

Remove or narrow will-change when an element no longer needs it.

Batch Reads and Writes

GSAP batches updates internally. When mixing GSAP with direct DOM reads/writes or layout-dependent code, avoid interleaving reads and writes in a way that causes repeated layout thrashing. Prefer doing all reads first, then all writes, or let GSAP handle the writes in one go.

Many Elements: Staggers and Lists

• Use stagger instead of many separate tweens with manual delays when the animation is the same.
• For long lists, consider virtualization or animating only visible items; avoid creating hundreds of simultaneous tweens if it causes jank.
• Reuse timelines where possible; avoid creating new timelines every frame.

Frequently Updated Properties

Prefer gsap.quickTo() for properties that update often, such as mouse-follower x/y. It reuses a single tween instead of creating new tweens on each update.

let xTo = gsap.quickTo("#id", "x", { duration: 0.4, ease: "power3" }),
    yTo = gsap.quickTo("#id", "y", { duration: 0.4, ease: "power3" });

document.querySelector("#container").addEventListener("mousemove", (e) => {
  xTo(e.pageX);
  yTo(e.pageY);
});

ScrollTrigger and Performance

• pin: true promotes the pinned element; pin only what is needed.
• scrub with a small value, such as scrub: 1, can reduce work during scroll; test on lower-end devices.
• Call ScrollTrigger.refresh() only when layout actually changes, such as after content load. Debounce refresh calls when possible.

Reduce Simultaneous Work

• Pause or kill off-screen or inactive animations when they are not visible, such as when the user navigates away.
• Avoid animating huge numbers of properties on many elements at once; simplify or sequence if needed.

Best Practices

• Animate transform and opacity where possible; use will-change only on elements that actually animate.
• Use stagger instead of many separate tweens with manual delays when the animation is the same.
• Use gsap.quickTo() for frequently updated properties.
• Clean up or kill off-screen animations; call ScrollTrigger.refresh() when layout changes, debounced when possible.

Do Not

• Animate width, height, top, or left for movement when x, y, or scale can achieve the same look.
• Set will-change or force3D on every element just in case; reserve them for elements that actually need them.
• Create hundreds of overlapping tweens or ScrollTriggers without testing on lower-end devices.
• Ignore cleanup; stray tweens and ScrollTriggers keep running and can hurt performance and correctness.