The industry-standard animation library for Flash

Crazy fast

Performance is paramount, especially on mobile devices with sluggish processors. Silky smooth animation is the hallmark of any tweening engine worth its weight and GSAP outperforms old “industry standards” by literally 1000%+ under stress. What was jerky and twitchy is now fluid. It’s the result of countless optimizations made to ensure that your interactive projects are responsive, efficient, and buttery smooth. Check out the speed test for a head-to-head comparison.

Freakishly robust

Built for professionals, GSAP is packed with features that make most other engines look like cheap toys. Animate colors, beziers, css properties, arrays, scrolls and lots more. Round values, smoothly reverse() on the fly, use relative values, automatically accommodate getter/setter functions, employ virtually any easing equation, and manage conflicting tweens like a pro. Define callbacks, tween in seconds or frames, build sequences effortlessly (even with overlapping tweens), repeat/yoyo and more.

Animate anything

That’s right. Anything. No predefined list of properties to choose from. Any numeric property of any object can be tweened, and if the property needs special handling (like colors, filters, non-numeric values, etc.), chances are there’s a plugin that will do it. If not, one can be created. The possibilities are endless.

Lightweight & expandable

Modular, flexible, and ultra-efficient, its plugin architecture keeps the core engine tight while allowing virtually any feature to be added via optional plugins. TweenLite packs an amazing amount of power into a surprisingly small package (under 7kb in all flavors).

Advanced sequencing

ou’re not limited to “one-after-the-other” sequencing; have animations overlap as much as you want. Nest timelines inside other timelines. Insert gaps, callbacks, labels, staggered tweens, and more. You get precise control over timing and unprecedented flexibility to create expressive animations with minimal code.

Permissive license

Completely free for everything except a very specific type of commercial use (reselling to multiple customers), GreenSock’s license makes it extremely accessible and business-friendly while providing a small funding mechanism to sustain ongoing support, enhancement, and innovation. The web is littered with abandoned “open source” projects, but GreenSock has a years-long track record of commitment to the platform.

View All Features

What is GSAP?

The animation platform consists of the following core tools, plus quite a few plugins, eases (including CustomEase and RoughEase), and special utilities like SplitTextField, BlitMask.

Note: the ActionScript versions of GSAP are no longer actively developed, as the market shifted to HTML5/JavaScript around 2012. Our customer base made it clear that they prefer we focus our energy there. We're very actively developing the JS flavor of GSAP. You're still welcome to use the ActionScript tools, of course; they're just not being actively supported any longer.


A super-lightweight version of TweenLite for when every byte counts.


TweenLite is an extremely fast, lightweight, and flexible animation tool that serves as the foundation of the GreenSock Animation Platform (GSAP).


TweenMax extends TweenLite, adding many useful (but non-essential) features like repeat(), repeatDelay(), yoyo(), updateTo(), and more.


TimelineLite is a lightweight, intuitive timeline class for building and managing sequences of TweenLite, TweenMax, TimelineLite, and/or TimelineMax instances. You can think of a TimelineLite instance like a container where you place tweens (or other timelines) over the course of time.


GSAP's most powerful and feature-packed sequencing tool, which supports repeat(), yoyo(), additional methods for working with labels and lots more.

View GSAP plugins Docs

Featured Examples and Showcases

Unique design with some smooth animations


Some great transitions and beautiful photos


Agency site with some neat effects

View All Examples and Showcases


Version: 2.1.3 updated 2019-05-18




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