Most UI motion today is designed in one tool and built again in another. A designer animates a transition in Figma or After Effects, then a developer recreates it in code. Details get lost, and every change repeats the cycle.
We use the phrase Motion Development Environment for tools that remove that second step. Instead of a video or a reference prototype, the output is a file that describes the interactive behaviour itself: the states a component can be in, the transitions between them, the inputs that change it and the events it sends back to the app.
ExodeUI is built this way. It is a browser and desktop tool where you design interactive UI and animation with state machines, spring physics, inputs and events. The work is saved as one open .exode JSON file, and runtime packages for React, Vue, Svelte, Angular, Solid, React Native, SwiftUI and Flutter play it. Your code sets inputs, such as a boolean for "loading" or a trigger for "success", and listens for events.
Because the file is plain JSON, developers can read it, and AI coding tools can edit it too. ExodeUI has an MCP server so Claude Code, Cursor and similar tools can create and change animations from plain-language prompts.
Rive is the best-known tool with a similar idea of a visual editor plus runtimes. Timeline tools such as After Effects remain better for video and illustration. The right choice depends on whether your motion needs to respond to the user or only play.