How to Tell If a Website Uses GSAP

GSAP (the GreenSock Animation Platform) is the leading professional web-animation library, behind a large share of the web's most polished scroll effects, timelines and interactive motion. Because it exposes a clear global, detecting it is straightforward: type gsap into the console or look for gsap.min.js in the Network tab. This guide covers every reliable signal, the animation architecture behind them, the look-alikes to rule out, and what GSAP usage tells you about the team.

What is GSAP?

GSAP, made by GreenSock, is a robust, high-performance JavaScript library for animating anything on the web — DOM elements, SVG, canvas, and more — with precise control over timing, sequencing and easing. Its core strengths are a powerful timeline system for choreographing complex sequences, excellent cross-browser consistency, and a suite of plugins, most famously ScrollTrigger for scroll-driven animation. It is the tool of choice for agencies, product launches, portfolios and award-style experiences where motion is central to the design, and it is widely used by the studios behind Awwwards-winning sites.

For detection, the key context is that GSAP is an animation library, so its presence tells you about the kind of site you are looking at: one that invests in motion and polished interaction. Finding GSAP signals a design-led, often agency-built site rather than a plain content page. Because GSAP registers a clear global object (and its plugins are recognisable), it is one of the easier libraries to confirm, and the specific plugins in use reveal what sort of animation the site does.

How GSAP loads and runs

A GSAP install loads the core library — gsap.min.js — commonly from a public CDN such as cdn.jsdelivr.net/npm/gsap or cdnjs.cloudflare.com, or bundled into the site's own JavaScript. At runtime it exposes the global window.gsap object, whose methods drive animation: gsap.to(), gsap.from(), gsap.fromTo() and gsap.timeline(). Plugins load separately and register with GSAP — most notably ScrollTrigger (ScrollTrigger.min.js, exposed as window.ScrollTrigger), but also Draggable, Flip, MotionPath and others.

The version era leaves a clue: GSAP 3 (current) consolidates everything into the single gsap object, while GSAP 2 and earlier exposed separate globals — TweenMax, TweenLite, TimelineMax, TimelineLite. So a gsap global indicates GSAP 3, while TweenMax/TweenLite indicate an older site. The presence of ScrollTrigger specifically tells you the site does scroll-driven animation (reveal-on-scroll, pinning, parallax). Knowing this — the gsap global, the gsap.min.js script, the plugin globals like ScrollTrigger, and the legacy TweenMax/TweenLite — makes detection quick and informative.

How to tell if a website uses GSAP

Confirm at least one strong signal (the global suffices).

1. Use the console. Type gsap and press Enter. A returned object with to, from and timeline methods confirms GSAP 3. Try TweenMax/TweenLite for older sites, and ScrollTrigger for the scroll plugin.

2. Check the Network tab. Filter for gsap. Look for gsap.min.js (and plugin files like ScrollTrigger.min.js), often from a CDN.

3. View the source. Search for gsap, greensock, TweenMax or ScrollTrigger. Script tags and inline animation code frequently reference them.

4. Note the plugins. A ScrollTrigger global indicates scroll-driven animation; other plugin globals (Draggable, Flip) reveal the animation features in use.

5. Observe the motion. Polished, choreographed scroll and timeline animation on the page corroborates GSAP, though the global is decisive.

What the GSAP signals look like

<script src="https://cdn.jsdelivr.net/npm/gsap@3/dist/gsap.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/gsap@3/dist/ScrollTrigger.min.js"></script>
window.gsap = { to: ƒ, from: ƒ, timeline: ƒ, registerPlugin: ƒ, … }
window.ScrollTrigger = { … }   // legacy: window.TweenMax / TweenLite

The window.gsap global (or legacy TweenMax/TweenLite) is conclusive, and ScrollTrigger reveals scroll-driven animation.

GSAP versus other animation libraries — avoiding false positives

Match the global to keep animation tools distinct. GSAP uses window.gsap (or TweenMax/TweenLite); Framer Motion is a React library leaving no single global but recognisable by its motion components and React presence; Anime.js uses window.anime; Lottie uses bodymovin/lottie and JSON animation data; AOS (Animate On Scroll) uses data-aos attributes and an AOS global. The gsap global is unique and unambiguous. Do not confuse GSAP with CSS-only animations or simple scroll libraries — GSAP's global and timeline API are distinctive. The presence of GSAP alongside a framework (React, Vue) is common and not contradictory; GSAP is framework-agnostic.

How reliable is each GSAP signal?

The window.gsap global is definitive, as are the legacy TweenMax/TweenLite globals. A gsap.min.js script (or bundled equivalent confirmed by the global) is strong. The ScrollTrigger global is conclusive for the scroll plugin. The observed motion is suggestive but not decisive alone. There is essentially no false-positive risk once you see the gsap global. As a rule, the console check settles it immediately, and the plugin globals tell you which animation features the site uses.

What GSAP usage reveals about a site

Finding GSAP signals an animation-heavy, design-led site built by a team that invests in motion and polished interaction. It is especially common on agency portfolios, product-launch pages, creative and brand sites, and award-style experiences, where choreographed animation is central to the design. The plugins in use refine the picture: ScrollTrigger indicates scroll-driven storytelling (parallax, reveals, pinning), while Draggable or Flip indicate interactive or layout animation. Its presence tells you the site prioritises craft and experience over minimalism, and that a skilled front-end developer or studio was involved. If you sell to agencies, creative studios, or design-forward brands, a GSAP site marks exactly that audience. The version (GSAP 3 versus legacy TweenMax) also indicates how recently the animation code was written.

What finding GSAP means for sales, agencies and competitive research

For sales and prospecting, GSAP marks a design-led, craft-focused site — a fit for creative tools, agencies, and services aimed at brands that invest in experience. Its presence suggests a budget for polished work.

For agencies and consultants, finding GSAP on a prospect's site tells you they already value motion, so the conversation is about elevating it further; finding it on a competitor's portfolio reveals the calibre of their interactive work. ScrollTrigger usage specifically signals scroll-storytelling expertise.

For competitive and market research, GSAP adoption indicates how much a competitor invests in front-end craft and experience. Spotting it (especially with ScrollTrigger) suggests award-style ambitions, useful when benchmarking design quality and the studios a brand works with.

GSAP in the wider front-end stack

GSAP is framework-agnostic and sits in the interaction layer, so it pairs with whatever the site uses for structure — vanilla JS, React (often with a wrapper), Vue, or a static build. On agency and creative sites it frequently accompanies WebGL/Three.js for 3D, Lenis or Locomotive Scroll for smooth scrolling, and a headless CMS for content. It is commonly loaded from a public CDN or bundled. For an auditor, the valuable details are the GSAP version (3 versus legacy), which plugins are present (ScrollTrigger and others), whether smooth-scroll or WebGL libraries accompany it, and the underlying framework; together these reveal a design-led team and the sophistication of its motion work.

A quick GSAP confirmation walkthrough

Open the site with developer tools on the Console panel and type gsap — a returned object with to/timeline confirms GSAP 3. Try ScrollTrigger to see whether scroll-driven animation is in use, and TweenMax/TweenLite on older sites. Switch to the Network tab, filter for gsap, and look for gsap.min.js and any plugin scripts. View the source for gsap, greensock or ScrollTrigger references. Scroll the page to observe the motion the library drives. The gsap global is enough to confirm GSAP and its plugins reveal the animation style.

A quick GSAP detection checklist

• Type gsap in the console; a returned object is conclusive (TweenMax/TweenLite for legacy).
• Check the Network tab for gsap.min.js and plugin scripts.
• Type ScrollTrigger to confirm scroll-driven animation.
• Search the source for gsap, greensock or ScrollTrigger.
• Use gsap (v3) vs TweenMax (v2) to gauge the version era.
• Note accompanying WebGL/smooth-scroll libraries to gauge animation ambition.

Detecting GSAP at scale

Checking one site is quick, but mapping animation-library adoption across many domains — to find design-led, craft-focused sites — calls for automation. StackOptic detects GSAP and thousands of other technologies from a real browser, reading runtime globals so it catches bundled installs that static scanners miss. Because GSAP so reliably marks design-led, craft-focused work, a market-wide scan for it — especially paired with WebGL and smooth-scroll libraries — is an efficient way to identify the agencies and brands that invest most in front-end experience, which is valuable whether you are recruiting talent, benchmarking competitors or prospecting creative tools. For related reading, see our guide to checking what JavaScript libraries a website uses and the full GSAP technology profile.