Playroom is a code-oriented design tool that lets developers and designers create UI prototypes directly in JSX using their own component library. It runs as a standalone web application with a CLI (`playroom start` for development, `playroom build` for static production bundles). The application renders an editable CodeMirror-based JSX editor alongside multiple live preview frames, where each frame can be configured per theme, screen width, and custom frame component. It also supports snippets, TypeScript prop autocompletion, an inspect mode, keyboard shortcuts, and shareable/preview URLs built from compressed state parameters. Architecturally, Playroom is a React application organized as a pnpm monorepo. The core package (`packages/playroom`) contains three entry bundles: the main editor (`entries/index.tsx`), the preview iframe (`entries/frame.tsx`), and the share-link preview mode (`entries/preview.tsx`). State is coordinated through a single reducer-based `StoreContext`, with IndexedDB persistence via localforage and debounced URL syncing. Webpack is used for both development and production builds, while vanilla-extract and sprinkles provide the styling system. The consumer-facing configuration surface is implemented through webpack aliases (`__PLAYROOM_ALIAS__*`) with default fallback modules, making the component, theme, snippet, and scope injection points cleanly extensible. This is firmly an application repository, not a data/research project. The only data-related work is application state management: compressed URL parameters with `lz-string`, browser storage, and static type extraction for editor hints. There is no analytical pipeline, dataset ingestion, or model training code. The repository is actively maintained with a release workflow, Cypress end-to-end tests, and Vitest unit tests. Known technical debt includes a temporary CodeMirror 5 stop-gap wrapper pending a CodeMirror 6 migration, reliance on React fiber internals for inspect mode, and a large custom webpack configuration surface.