While scroll-based animations are all based on the same concepts, there are actually many different tools you can use to implement them.
The first, and most obvious, is by coding them from scratch. This is always an option, but not what we're going to discuss in this post. If you're here, you already know that using a library to implement scroll animations can save you lots of time.
There are lots of libraries out there to help with this (I've analyzed over 30 in my guide to scroll-triggered animation libraries). So which scroll-based animation library is the best?
There are lots of things to consider when choosing a scroll animation library to use in your project. Here's some of them:
- Scroll-triggered or scroll-bound support
- Tweening support
- Scroll-pinning support
- Browser support
- Speed and performance
- Package size
- License and price
I've spent hours researching, collecting data, and testing the scroll-based animation libraries available today (there are a ton of them). Some are very similar, and some are quite different from each other.
Really the most important thing to consider is going to be whether or not the library offers support for the type of scroll animation that you need to build. After all, that's why you're using the library in the first place: to accomplish a specific task.
You also have to consider the library's license: is it free for commercial use? (That's the most common question!)
If you don't have the budget, it's important to choose a library that has the MIT license (or similar) if you're working on a commercial project. If it's a personal project that you're not profiting off of (for example, selling work to a client) then in general you should be covered under most licenses. But it's important to always double check this.
Flexibility is an important and often overlooked attribute when choosing a scroll animation library. Certain libraries may allow you to implement the same effect, but not all of them allow you to customize them to your exact needs, as well as provide events to hook into if you need to do additional work.
So, considering all of the different options and attributes, which scroll-based animation library is the best?
My pick for the best library for creating simple scroll-triggered animations is Sal.js. If you're new to web development or just need a simple and quick way to add a fade-in animation to your page, this is the library you want. It's easy enough to drop in to a project but offers options for customization.
Pros of Sal.js: Sal.js is very beginner-friendly and contains 10+ built-in animations for you to use right away. It's also pretty customizable: you can use your own CSS animations with it as well as easily enable and disable animations and hook into in/out events. It is only 1.3kb when minified and gzipped, which is pretty darn tiny! It's licensed under the MIT License, so it's free for commercial and personal use.
Cons of Sal.js: Sal.js animations are triggered based on how much of an element is visible in the viewport. While it offers some customization of this, it's more difficult to fully customize a scene. Also, it can be buggy in some browsers when using repeated animations.
When you should use Sal.js: Use this library if you need to create simple scroll-triggered animations using CSS classes.
Cons of GSAP ScrollTrigger: While they offer lots of demos and great API documentation, ScrollTrigger is not as beginner-friendly as other scroll animation libraries out there (mostly because you also need to learn to use GSAP itself to implement ScrollTrigger. If you already have GSAP experience, it's not as difficult). It's considerably larger than other libraries as well: if you include GSAP and ScrollTrigger in your project, you'll add around 30kb minified and gzipped to your project, which puts it on the larger side for a scroll animation libraries.
When you should use GSAP ScrollTrigger: Use ScrollTrigger if you need to create a highly-interactive page with multiple complex scroll-bound animations.
There is no overall "best" option when it comes to scroll animation libraries. There is only the best for your use case! While I've picked Sal.js and ScrollTrigger to represent the best libraies for simple and advanced scroll-based animations, there are many more that represent the inbetween.
I wrote a guide to the top 10 libraries used to create scroll-triggered animations. It compares and contrasts each library based on the criteria above so you can choose the exact right one for your needs and skill level. It even has a handy comparison chart for quick reference.