A whiteboard where every box opens.

Draw the big picture. Then open any box, or any arrow, and find a whole whiteboard or a page of notes inside it. Go as deep as the idea goes.

Free for public projects. No card.

Top sheet

deposit

Try it. Stacked boxes have a whiteboard inside. Boxes with a page icon have notes.

What a box can hold

A page of notes
Click a box and write beside it: headings, lists, images, code. The notes open in a side panel, so the drawing stays where it is.
Another whiteboard
Double-click to go inside. The box becomes a sheet of its own, with boxes of its own. A trail of tabs shows how deep you are and leads back out.
Something that already exists
Link the same page from five places. It is one page, not five copies: edit it once, and every place that links to it shows where else it is used.

Arrows and groups hold things too. Everyone you invite edits together, live, with cursors. People who only need to look can watch for free.

Plan a move: Visa, apartment, budget. Each one opens into its own steps.
Map a system: Services on top. Inside each, how it works. On each arrow, the contract between them.
Outline a course: Weeks as boxes. Readings and notes inside each week.
Write a story: Acts, then scenes, then the page itself.

You pay for people who edit private work. Nothing else.

per editor, per month

Open source