localStorage auto-save. The editor debounces a write to localStorage 600 ms after your last edit. Refresh the page or come back tomorrow and your design is there. No account needed.
Cloud save (optional). Sign in with email and your projects sync to a Supabase project keyed to your user-id. Same auto-save cadence; works across devices, browsers, and keeps a single source of truth.
JSON export. Download the full project as a plain JSON file. Useful for portfolio archives, sharing with collaborators, or just keeping a clean backup outside the browser.
The JSON shape is a Project: panels (each with its layers and optional per-panel background), rowLayers (spanning layers), global (background, language list, active language, project name, autosave preference, export formats), and panelW / panelH. No binary blobs aside from inline data-URLs for uploaded screenshots.
500-step history kept in-memory per session. Ctrl/Cmd+Z to undo, Ctrl/Cmd+Shift+Z to redo. History resets when you load a different project but is preserved across the auto-save cycle.