Quick take (read this first)

The idea in two sentences. Excalidraw is the beloved open-source virtual whiteboard: fast, hand-drawn, no-login sketching. Dim0 is what happens when you keep that open, spatial canvas but add Notion-grade notes, code nodes, and an AI agent that reads and acts on the whole board.

Where Dim0 wins

  • Every kind of node, not just shapes: rich Markdown notes, code, charts, docs, nested boards, mini-apps.
  • A board-aware AI agent that turns notes into mind maps, runs code, and writes results back as nodes.
  • Structure that persists: nested boards and organized content, not one flat sketch.
  • Presentation mode: drop frames and present straight from the board.

Where Excalidraw wins

  • Radical simplicity. Open a tab, start drawing, no account needed.
  • The hand-drawn aesthetic that made it famous, and a lighter, faster feel for pure diagramming.
  • Battle-tested, hugely adopted, and embeddable as a library in other apps.
  • Nothing to learn. It does one thing beautifully.

Both share the thing that matters most to this crowd: open-source. They even resolve edit conflicts in a similar spirit, last-write-wins rather than CRDT (Dim0 uses operational transforms; Excalidraw uses version-based reconciliation). Dim0 is also self-hostable.

Pick Dim0 if you want a real workspace, notes and code and AI on the canvas, not just a drawing. Pick Excalidraw if you want the fastest, simplest, most delightful way to sketch a diagram and get out.

The job you're actually trying to do

You reach for a whiteboard when thinking gets visual: a system diagram, a flow, a rough map of an idea. Excalidraw nails that first sketch. The question is what happens next, when the sketch needs notes around it, data pulled in, code run, or an AI to help build on it. That's the seam between the two tools.

What Excalidraw is (fairly)

Excalidraw is an open-source virtual whiteboard with a distinctive hand-drawn style. It's fast, it's free, it needs no login for basic use, and it has become the default for quick technical diagrams. It supports real-time collaboration and can be embedded as a component in other products. Recent versions even generate diagrams from a text prompt.

Its design philosophy is do one thing well: freehand shapes and diagrams, with as little friction as possible. That focus is exactly why people love it, and exactly where it stops.

What Dim0 is

Dim0 keeps the open, infinite, collaborative canvas, then treats shapes as just one node type among many. On the same board you get Notion-grade rich notes, sandboxed code nodes, live charts, uploaded documents, nested boards, generated mini-apps, and a board-aware AI agent. Your freehand sketches aren't just decoration: the agent can read them as context. It's MIT-licensed and self-hostable, and its custom engine (canvas-harness) handles thousands of nodes smoothly.

Head to head

Dim0 Excalidraw
Open source Yes (MIT) Yes (MIT)
Freehand shapes Yes Yes (its whole thing)
Rich Markdown notes Yes No
Code nodes / charts / docs Yes No
Board-aware AI agent Yes Text-to-diagram only
Mini-apps (interactive) Yes No
Nested boards / structure Yes Flat scene
Presentation mode Yes Frames (basic)
Real-time collaboration Yes Yes
Self-host Yes Yes
Simplicity / speed to first sketch Good Best

Where Excalidraw is genuinely better

If all you want is the sketch, Excalidraw wins on friction. No account, no concepts, instant. The hand-drawn look is genuinely nicer for throwaway diagrams, it's lighter, and it's embeddable in a way Dim0 isn't. For "I need a quick architecture diagram to paste in a PR," Excalidraw is the right tool and Dim0 is overkill.

Where Dim0 pulls ahead

The gap opens the moment a sketch needs to become work:

  1. Notes, code, and data on the same canvas as the drawing, all connected.
  2. An agent that acts on the board. Select some notes, get a mind map. Ask it to pull benchmarks and chart them. It writes back as editable nodes.
  3. Structure that lasts. Nested boards keep a big project organized instead of one sprawling scene you eventually abandon.

Same open-source values, a similar last-write-wins sync philosophy. Dim0 is the whiteboard that keeps going after the sketch.

So which should you use?

  • A fast throwaway diagram: Excalidraw.
  • A living workspace where sketches, notes, code, and AI coexist: Dim0.
  • If you already love Excalidraw's canvas feel, Dim0 will feel familiar, it just doesn't stop at shapes.

Try it: app.dim0.net: open-source, self-hostable, free to start.