Lottie JSON vs .lottie Format — What's the Difference and Which Should You Use?

Two file formats. Same animations. Very different performance characteristics. If you've used Lottie before, you know the .json file — you export it from After Effects with the Bodymovin plugin, drop it into lottie-web, done. But there's a newer format: .lottie. It's a binary container that replaces the JSON, and if you're starting a new project, it's worth understanding the difference. What is Lottie JSON? The original format. A .json file that describes vector animations: shapes, keyframes, layers, colors, timing. It's plain text, human-readable, and widely supported. Pros: Works everywhere Lottie is supported Human-readable (you can inspect and edit it) Supported by every tool and library Cons: Large files (uncompressed JSON with lots of repeated data) No built-in support for multiple animations in one file No metadata or preview image support What is .lottie? The .lottie format (sometimes called dotLottie) is a ZIP container with a .lottie extension. Inside it contains: The animation data (compressed JSON) A manifest.json describing the file Optional preview images Optional multiple animations in one container It was developed by LottieFiles and adopted as the preferred format for modern Lottie tooling. Pros: ~30-70% smaller than equivalent JSON (thanks to compression) Can contain multiple animations in one file Supports preview thumbnails Cleaner API in the @lottiefiles/dotlottie-web renderer Cons: Binary format — not human-readable Requires the dotLottie player (not the older lottie-web) Slightly less universal support File Size Comparison For a typical 2-second UI animation: Format Typical Size Lottie JSON (.json) 40 – 120 KB dotLottie (.lottie) 15 – 50 KB The size reduction comes from standard ZIP compression applied to the JSON content. It's meaningful on mobile connections. Converting Between Formats The easiest way to convert between .json and .lottie formats is using the free browser-based tools at IconKing . No signup required, no file size limits. Just