Diagramming Tool

Drawing

Auto-layout diagrams

Sequence diagrams, ERDs, class diagrams, gantt charts and more lay themselves out. You edit the content by tapping the picture — never any code.

How they work

For a sequence diagram or an ERD, the arrangement carries no meaning — moving a participant two inches left says nothing. What matters is the content: who talks to whom, in what order, and what each thing is called. So these diagrams place themselves, and stay tidy however much you add.

You edit them by tapping the thing you want to change on the diagram itself. Tap a participant and its fields open; tap a message and you can retitle it, change its arrow or move it. Add more with the buttons at the bottom left. The layout re-flows around whatever you did.

What you can build

There are 20 auto-layout kinds:

Sequence diagram

Messages between services, clients and people, in order. You fill in participants and messages.

Entity relationship diagram

Database tables, their columns and how they relate. You fill in entities and relationships.

Class diagram

Types, their members and the relationships between them. You fill in classes and relationships.

State machine

States and the events that move between them. You fill in states and transitions.

Delivery plan

Phases, tasks, durations and milestones on a timeline. You fill in phases and tasks.

C4 container diagram

People, systems and the containers inside your system. You fill in elements and relationships.

User journey

Steps a user goes through, scored for how well they go. You fill in phases and steps.

Timeline

What happened when — good for architecture history. You fill in periods.

Kanban board

Work in progress, by column. You fill in columns and cards.

Mindmap

Break a system or problem into branches. You fill in branches.

Pie chart

Proportional breakdown of a total. You fill in slices.

Priority quadrant

Plot options against two axes — effort versus impact and friends. You fill in items.

Git branching

Branches, commits, tags and merges — how a team actually ships. You fill in branches and commits.

Requirements

What the system must do, and what proves that it does. You fill in requirements, elements and between requirements.

Packet layout

How a header or wire format is laid out, bit by bit. You fill in fields.

Sankey flow

Where a quantity goes — traffic, spend, funnel drop-off. You fill in stages and flows.

XY chart

Bars and lines over a shared axis — traffic, latency, revenue. You fill in x axis and series.

Radar comparison

Score two or three options against the same set of criteria. You fill in criteria and options.

Treemap

Nested proportions — cloud spend, codebase size, revenue mix. You fill in boxes.

Fishbone

Cause and effect for an incident or a defect, grouped by theme. You fill in causes.

Fields that reference other rows

Where a field points at something else in the diagram — the From and To of a sequence message, the two ends of an ERD relationship, the phase a gantt task belongs to — it is a picker of the things that actually exist, not a free-text box. Rename a participant and every message that referenced it follows. You cannot draw an arrow to a service that is not there.

Frequently asked

Do I have to write Mermaid or PlantUML?
No. Auto-layout diagrams are edited by tapping items on the picture and filling in fields. Diagram source is an internal detail you never see or write.
Can I move things on an auto-layout diagram?
Not by dragging — the layout owns positions, which is what keeps it tidy as it grows. Reorder the rows instead, and the picture follows. If you need to place things yourself, use a free-form canvas.

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