Use this free browser-based Lottie player to preview, adjust speed, and inspect JSON animation files. No account needed, 100% client-side Lottie viewer.
AI Generation Prompt
Technical Specification: Free Lottie Animation Player & Speed Controller
Overview
A high-performance, single-file browser utility designed for motion designers and frontend developers to preview, inspect, and manipulate Lottie JSON animations. The application focuses on speed, clarity, and ease of use, operating entirely within the user's browser memory.
Core Features
- Drag-and-Drop Loader: Intuitive zone for importing .json Lottie files.
- Playback Controls: Play, pause, restart, and frame-by-frame navigation.
- Speed Customization: Variable playback speed (0.25x to 2x).
- Visual Testing: Background color switcher to verify visibility on different interface themes.
- Loop Toggle: Switch between looping and single-play modes.
- JSON Inspector: A read-only view of the raw animation JSON code for debugging.
- Metadata Viewer: Display animation dimensions, frame rate, and total frame count.
UI/UX Design
- Aesthetic: Clean, vibrant light-mode design. Use a palette of soft whites (#ffffff), light grays (#f9fafb), and deep slate for text (#1f2937). Use a crisp blue (#2563eb) for primary actions.
- Layout:
- Header: Functional title and file selection button.
- Main Area: A split-pane layout. Left: Preview canvas with background selector. Right: Control dashboard (play/pause, speed, loops) and statistics.
- Bottom Section: Collapsible panel for viewing the source JSON code.
- Interactions: Use smooth CSS transitions for button states and modal appearances. Playback speed changes should take effect immediately without re-initializing the entire animation.
Technical Directives
- Architecture: Must be a single HTML file containing internal CSS and Vanilla JavaScript.
- Library: Use
lottie-webfrom a reliable CDN. Do NOT bundle or minify in a way that prevents source code review. - Storage Rules (STRICT): NO
localStorage,sessionStorage, orcookies. All data must be held in JavaScript variables. Application must be compatible with a null-origin sandboxed iframe. - Responsiveness: Use CSS Grid and Flexbox to ensure the control panel and preview area wrap cleanly on smaller mobile screens.
- Security: Do not use
eval()or dangerous DOM manipulation. Sanitize all file inputs. Always usetarget="_blank"for any external documentation links. - No Dark Mode: Force a strict light-mode design with high-contrast UI elements suitable for bright environments.
Spread the word
Files being used
Frequently Asked Questions
Everything you need to know about using this application.
How do I load a Lottie JSON file into this viewer?
To load a Lottie file, simply click on the 'Upload' area or drag and drop your .json file directly into the main application window. The application processes the file client-side, ensuring your data never leaves your browser. Once the file is parsed, the animation will automatically begin rendering in the preview window. You can swap files at any time by simply uploading a new one, which will clear the previous animation from memory to ensure privacy and performance.
Can I adjust the playback speed of the animation?
Yes, this tool includes a dedicated speed control feature located in the playback toolbar. You can select playback speeds such as 0.5x, 1x, 1.5x, and 2x to test how your animation handles different pacing requirements. This is particularly useful for motion designers who need to verify that easing curves and keyframes remain visually consistent when the animation is sped up or slowed down for different interface contexts.
Does this tool store my animation files?
Absolutely not. This tool is built with a strictly stateless architecture. No animations, JSON files, or user preferences are ever saved to localStorage, indexedDB, or any remote database. When you refresh the page or close your browser tab, all loaded animation data is purged from your device's memory. This provides a secure environment for viewing sensitive or proprietary design assets.
What libraries are used to render these animations?
This application utilizes the industry-standard Lottie-web player library, loaded via a secure CDN. This ensures high-fidelity rendering that matches the output seen in major design software and production environments. By leveraging standard rendering engines, we ensure that your preview is accurate to the underlying code. The tool provides a clean interface around this engine, focusing on utility and ease of use rather than adding unnecessary bloat.
