wtf is lottie-ios?

Lottie for iOS is an open-source library created by Airbnb that lets designers' animations run natively inside iPhone and iPad apps, no extra work needed from engineers to recreate them by hand. It bridges the gap between what a designer creates and what actually ships in the app. Here's how it works: a designer creates animations in Adobe After Effects (a professional animation tool) and exports them as a lightweight JSON file (a text-based data format). Lottie takes that JSON file and renders the animation smoothly on the device, playing it, looping it, reversing it, speeding it up, or even allowing users to interact with it by scrubbing through frame by frame. The practical benefit is significant for teams building apps: instead of a back-and-forth where engineers approximate what designers intended, you get pixel-perfect animations from the original design file. Because the animations are stored as data rather than video, they scale perfectly to any screen size and stay tiny in file size even when visually complex. This library is specifically for iOS, macOS, Apple TV, and Apple Vision Pro apps built in Swift (Apple's programming language). Airbnb also maintains equivalent versions for Android and the web, making Lottie a cross-platform standard for app animations across the industry. Many of the loading spinners, success checkmarks, and delightful micro-animations you see in popular apps are powered by Lottie behind the scenes.