DiagramTool

Flowcharts from text, including Mermaid

The Flow tab is for processes: intake, decisions, hand-offs, and BPMN-style events. You can write DiagramTool’s native diagram: flow DSL, paste a Mermaid flowchart / graph, or open a .mmd file. Draw.io files also land here as flow boards.

Open the Flow tab

Native flow DSL

Start and end nodes are first-class. Everything else is a node with a type:. Default nodes are rounded process boxes. Other shapes:

Optional captions include label, system (owning service), duration, assignee, and lane. Edges use A -> B or A ->|yes| B. Unlike architecture mode, flow connectors stay on the animated bezier style — orthogonal edges: is an architecture-only keyword.

diagram: flow
title: Refund decision

start Request
node Eligible {
  type: decision
  label: Within policy?
}
node Refund { label: Issue refund }
node Escalate { label: Manual review }
end Done

Request -> Eligible
Eligible ->|yes| Refund -> Done
Eligible ->|no| Escalate -> Done

Swimlanes

Declare lane Customer { color: '#FDE68A' } (and other actors), then set lane: Customer on nodes. The canvas draws horizontal bands with the lane name on the left. Swimlanes always lay out left-to-right inside each band, even if you set direction: on a mixed document. Templates include a loan-application swimlane and BPMN event / subprocess starters if you want a working file instead of a blank editor.

Mermaid flowchart import

If the first significant line is flowchart or graph, DiagramTool treats the file as Mermaid flow. File → Open and raw import convert that source toward the native flow DSL so the rest of the workspace (pins, export, templates) can use it. You can also copy native flow back out as Mermaid via the mermaid helper. This is flowchart/graph only — a sequenceDiagram belongs on the Sequence tab, and a Mermaid gantt is imported as a Gantt board, not a flowchart.

flowchart LR
  Request[Refund request] --> Eligible{Within policy?}
  Eligible -->|yes| Refund[Issue refund]
  Eligible -->|no| Escalate[Manual review]

draw.io as a flowchart, not an architecture model

Opening a .drawio / diagrams.net file maps rectangles, ellipses, diamonds, and basic flowchart stencils onto flow nodes, plus edges that have both ends. Swimlanes, groups, tables, images, extra pages, and unclassified shapes are skipped (you see a skip list — they are not silently dropped). Infra icons do not become architecture cloud nodes. Details live on the local-first and draw.io page.

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