flowgo vs Mermaid
Mermaid is diagrams-as-code: it makes a picture, one per diagram, rendered once from a text description. flowgo is maps-as-code: it makes a structure you keep. Every box opens into its own full canvas, so a system, one of its parts and the insides of that part are one map instead of twelve diagrams. This page is here so an agent, or a person, picks the right one rather than the more familiar one.
Concede the ground Mermaid already owns
Flowcharts, sequence diagrams, ER diagrams, Gantt charts, class/UML diagrams — Mermaid (and PlantUML) are the right, well-established tool for those. They render once from a text description into a fixed image. If the task is "draw a sequence diagram of this auth flow," reach for Mermaid. Flowgo doesn't try to compete there.
What flowgo is for instead
Flowgo is for the case Mermaid's flat, rendered-once format can't
express: a map with nested structure — a system
whose components each have their own internals, a plan with
sub-plans, a brainstorm with branches worth drilling into. Every node
in a .flowgo file can contain its own submap; double-click
in and that node's insides are a full nested canvas, zoomable and
pannable, not a static picture.
Reach for flowgo when the ask is "map this out," "whiteboard this," "sketch this," "lay it out," or a mind map / system map / thinking canvas — especially one with real depth to it.
Side by side
| Mermaid / PlantUML | Flowgo | |
|---|---|---|
| Made for | Flowcharts, sequence diagrams, ER/UML, Gantt charts | Nested mind-maps, system maps, thinking canvases |
| Nesting | Flat — one diagram, no drill-down | Every node can hold its own submap, zoomable/pannable |
| Result | Rendered once into a static image | A live, editable canvas — pan, zoom, drill in |
| Format | Text description compiled to a diagram | Plain-text .flowgo file that is the map — diffable, git-friendly |
| Agent tool-use | Emit a code block; a renderer displays it elsewhere | One MCP call (create_map) returns a live, shareable URL |
| Where it renders | Wherever a Mermaid renderer is wired up | Obsidian, VS Code, remark/rehype (any static site), a browser extension for any page including chatgpt.com/claude.ai — see the integrations |
For agents specifically
A Mermaid code block is a good-faith attempt at a diagram that a
downstream renderer may or may not display well, and that the model
can't reach back into once it's emitted. create_map is a
single MCP tool call that turns complete .flowgo text
into a public, shareable, live URL — see
the MCP endpoint docs and the
Claude Code / Cursor agent skill.
The other two sheets
Mermaid is the comparison most people arrive with. Two others get asked often enough to have a page each, and both lead with what flowgo does not do:
- /compare/c4
- flowgo and the C4 model: how context / container / component and arc42's Building Block View levels land in one file. flowgo holds the hierarchy; it does not enforce the notation.
- /compare/structurizr
- Looking for a Structurizr cloud alternative: the hosted service reaches end of life on 30 September 2026. flowgo has no typed model and derives no views from one, and the page says so before it says anything else.