Mermaid error

Square brackets inside a label end the node early

Reproduced on Mermaid 11.17.2 · Updated 11 September 2026

Square brackets inside a label end the node early in Mermaid. The exact parser message, why it happens, and corrected source that renders.

What Mermaid says

Parse error on line 2:
...owchart TD  A[Item [1] ready] --> B[Nex
----------------------^
Expecting 'SQE', 'DOUBLECIRCLEEND', 'PE', '-)', 'STADIUMEND', 'SUBROUTINEEND', 'PIPE', 'CYLINDEREND', 'DIAMOND_STOP', 'TAGEND', 'TRAPEND', 'INVTRAPEND', 'UNICODE_TEXT', 'TEXT', 'TAGSTART', got 'SQS'

Why it happens

The first closing square bracket ends the node definition, so the characters after it are read as a new statement on the same line.

The source that fails

flowchart TD
  A[Item [1] ready] --> B[Next]

How to fix it

Quote the label so the inner brackets stay part of the text.

flowchart TD
  A["Item [1] ready"] --> B[Next]

The corrected source, rendered with Mermaid 11.17.2.

Next steps

Paste your own version into the Mermaid repair tool, which applies this correction and fourteen others and shows every change. The related page covers the surrounding syntax, and the error dictionary lists every message.