Lottie Inspector & Compactor

What it is for

Lottie Inspector & Compactor examines an animation as JSON data. It reports composition size, frame rate, duration, layers, keyframes, path points and references. It also checks whether the file can be opened as an editable Motion Desk project.

Use inspection before integrating an unfamiliar animation, comparing exported files or preparing a small shape animation for editing. The inspector does not run expressions, render arbitrary compositions or download referenced images. A report describes the data and supported editor subset; it is not a guarantee of playback in every Lottie player.

Worked example

Run the supplied two-layer animation without changing its settings. The report identifies a 480 by 360 pixel composition at thirty FPS. Ninety frames span three seconds. It counts shape layers and transform keys, then checks whether every rendering feature fits Motion Desk.

Download the compact Lottie file. Its JSON has no formatting whitespace, while its rendering fields remain unchanged. Open the editable project to adjust supported vector shapes and transforms. Imported transforms are sampled at each composition frame, so subframe interpolation can differ from the source.

For a second example, use the blank composition with root metadata and select Remove root metadata. This removes only the top-level meta field. Other names, asset references, expressions, colors and keyframes remain in the compact file.

How to read the result

Before and after sizes count UTF-8 bytes. Saved bytes are their difference. A file that is already compact may show no saving; unusual escaping can even make serialization larger. Compaction does not optimize geometry, remove invisible artwork or reduce keyframes.

The report groups layer and shape operator types and counts expressions and external asset references. Its editor issue explains the first unsupported feature found. An unsupported file still receives general inspection and a compact download when it passes the data and size checks.

An editable project and editor link are returned only when the entire composition fits the supported subset. No partial import is presented as a complete conversion.

Tips and common mistakes

Motion Desk accepts solid 2D shape layers with static geometry and styles, static anchors, and animated position, scale, rotation and opacity. Parenting, text, images, precompositions, effects, masks, mattes, spatial motion paths and unsupported operators require another editor.

General inspection has a two-megabyte JSON limit, depth and value-count budgets, and checks finite numbers and valid timing. Editable imports additionally allow twenty-four layers, 360 frames, sixty FPS, sixty seconds, 4096 path points and a two-megapixel stage.

Keep an original file before editing. Frame-sampled transforms preserve supported appearance at composition frame times; they do not preserve the author's original animation curves or project structure.

FAQ

Will compaction change animation timing?

Whitespace removal preserves timing fields and all other rendering data. Optional metadata removal changes only the root metadata field. No temporal resampling occurs in the compact Lottie download.

Does a clean inspection mean external assets are safe?

The inspector only reports references. It never downloads or evaluates them. Check the animation and its assets separately in your intended playback environment.

Can I inspect through API or MCP?

Yes. Use flipline_lottie_inspector with Lottie JSON and an optional metadata-removal flag. The result includes the structural report, byte counts, compact artifact and compatible editable project link.