Excalidraw

Excalidraw is a virtual whiteboard that renders shapes with a hand-drawn line style. The aesthetic is deliberate: a diagram that looks sketched reads as a work in progress, which changes how a team treats it during a discussion. The product runs in the browser with no account required for a basic session. A drawing can be exported as an image or a file, shared through a link, and embedded in another page. For teams that need persistence and collaboration, an end-to-end encrypted room or a self-hosted deployment is available. The source is published and the project is widely embedded: several documentation tools and editors use Excalidraw's component rather than building their own diagram surface. That reuse is the clearest evidence that the drawing layer is separable from the hosted app.