Excalidraw

Open-source virtual whiteboard for creating hand-drawn style diagrams and sketches.

Open source alternative to:

Excalidraw is a virtual whiteboard tool that lets you create diagrams and sketches with a charming hand-drawn aesthetic. It runs entirely in the browser with no account required, making it fast and frictionless to start drawing.

It supports real-time collaboration, allowing teams to brainstorm and diagram together simultaneously. Excalidraw supports shapes, arrows, freehand drawing, text, and image embedding — everything you need for quick wireframes, flowcharts, and system diagrams.

Beyond the hosted app, Excalidraw ships as an embeddable React component (@excalidraw/excalidraw), making it easy to integrate into your own applications. With 100k+ GitHub stars and an MIT license, it is one of the most widely adopted open-source diagramming tools available.