Framerjs

Framer.js is a JavaScript-based prototyping library and tool used to build high-fidelity interactive user interface prototypes for web and mobile. It provides a frame-based, layer-oriented model in which visual elements are organized into nested layers and frames. Designers and developers can write code to specify layout, appearance, animation, and response to user input, enabling interactive prototypes that resemble the final product.

Key features include a layer/frame hierarchy, tweened animations and physics-based motions, event handling for common gestures such as taps, drags, pans, and pinches, and a timeline for sequencing changes. Prototypes can be previewed in a browser or in the Framer Studio environment, and can be exported as shareable HTML/JS pages. The library emphasizes a code-first approach, allowing designers to implement interactions directly in JavaScript.

Framer.js evolved into broader Framer products, including Framer Studio and Framer X, which broadened the tool to include design-time assets, components, and later React-based workflows. In the mid-to-late 2010s Framer shifted toward a React-centric approach, and Framer Motion emerged as an independent animation library for React. Today, Framer represents a design-and-code prototyping platform, while Framer.js as a standalone library is largely historical, superseded by newer tooling and architectures.