Which Mermaid Diagram Types and Features Does Mermaid ASCII Support?

Updated

Mermaid ASCII (v1.6.1) converts Mermaid diagram code into ASCII art. Based on the examples shown on the site, it supports flowcharts with nested subgraphs, labelled arrows, and styled text, as well as sequence diagrams. If your diagram relies on features beyond these, the tool may not render them correctly.

Diagram Types and Features with Confirmed Support

The site provides four worked examples, each demonstrating a specific capability:

Example Feature demonstrated What it shows
Example 1 Nested Subgraphs Flowcharts where subgraphs are contained inside other subgraphs
Example 2 Labelled Arrow Edges with text labels (e.g. `A -->
Example 3 Styled Text Text styling applied within diagram nodes
Example 4 Sequence Diagram Sequence diagrams, not just graph-type diagrams

The cURL example on the page also uses a basic flowchart (graph LR\nABC --> DEF), confirming left-to-right graph direction is supported.

Flowcharts and graphs

Flowchart syntax (graph LR, graph TD, etc.) is the primary use case. The examples cover:

  • Nested subgraphs — subgraphs within subgraphs render as nested ASCII boxes.
  • Labelled arrows — edge labels appear alongside the connecting lines.
  • Styled text — styled node text is preserved in the ASCII output.

Sequence diagrams

Example 4 confirms sequence diagrams are supported, so the tool is not limited to node-and-edge graphs.

Rendering Options That Affect Output

The interface exposes a few settings that change how the ASCII output looks:

  • xPadding (shown as 5) — horizontal spacing.
  • yPadding (shown as 3) — vertical spacing.
  • Use extended characters — a toggle for using extended ASCII/Unicode box-drawing characters instead of plain characters.

These affect layout and appearance, not which diagram types are accepted.

Alternative Ways to Generate the Same Output

The page lists two additional methods beyond the web interface, both using the same GitHub repository (AlexanderGrooff/mermaid-ascii):

cURL request:

curl https://mermaid-ascii.art -d mermaid="graph LR\nABC --> DEF"

Run locally with Go:

git clone https://github.com/AlexanderGrooff/mermaid-ascii
cd mermaid-ascii
go run main.go -f test.mermaid

The Go CLI method reads from a file (test.mermaid), which is useful for batch conversion or offline use.

What to Check Before Relying on It

The page only demonstrates the four features above. If your diagram uses other Mermaid constructs — such as class diagrams, state diagrams, Gantt charts, or pie charts — there is no evidence on the site that these are supported. For those cases, test your specific diagram code in the tool first, or use the Go CLI locally to check the output before committing to it in a document or README.