Accessibility features

Documentation Index

Fetch the complete documentation index at: https://mintlify.com/mermaid-js/mermaid/llms.txt

Use this file to discover all available pages before exploring further.

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Automatic ARIA attributes

• aria-roledescription - Set to the diagram type (e.g., “flowchart-v2”, “sequenceDiagram”)
• aria-labelledby - References the accessible title element
• aria-describedby - References the accessible description element

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Example SVG output

<svg
  aria-labelledby="chart-title-mermaid-1668725057758"
  aria-describedby="chart-desc-mermaid-1668725057758"
  aria-roledescription="flowchart-v2"
  xmlns="http://www.w3.org/2000/svg"
  width="100%"
  id="mermaid-1668725057758"
>
  <title id="chart-title-mermaid-1668725057758">This is the accessible title</title>
  <desc id="chart-desc-mermaid-1668725057758">This is an accessible description</desc>
</svg>

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Accessible titles

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Syntax

accTitle: Your title text here

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Example

<title id="chart-title-mermaid_382ee221">Big Decisions</title>

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Accessible descriptions

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Single-line description

accDescr: Your description text here

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Multi-line description

accDescr {
  This is a multiple line accessible description.
  It does not have a colon and is surrounded by curly brackets.
  You can include as many lines as needed.
}

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Example with multi-line description

<desc id="chart-desc-mermaid_382ee221">
  The official Bob's Burgers corporate processes that are used for making very, very big
  decisions. This is actually a very simple flow: identify the big decision and then make the big
  decision.
</desc>

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Examples by diagram type

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Flowchart

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Sequence diagram

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Class diagram

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Entity relationship diagram

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Gantt chart

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Git graph

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Pie chart

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State diagram

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User journey

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Requirement diagram

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Best practices

• Always provide titles - Screen readers announce titles when focusing on diagrams
• Write meaningful descriptions - Describe the purpose and key information, not just the visual structure
• Keep titles concise - Titles should be brief (1-10 words)
• Use multi-line for complex diagrams - Longer descriptions help users understand intricate diagrams
• Test with screen readers - Verify your accessibility features work with actual assistive technology

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Benefits

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For users with disabilities

• Screen readers can announce diagram titles and descriptions
• Alternative text provides context when visuals aren’t accessible
• ARIA attributes help assistive technologies understand diagram structure

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For all users

• Better SEO - Search engines index title and description content
• Improved documentation - Descriptions serve as documentation
• Context for complex diagrams - Helps everyone understand the diagram’s purpose

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Testing accessibility

1. Inspect the HTML - Check that <title> and <desc> elements are present
2. Use a screen reader - Test with NVDA, JAWS, or VoiceOver
3. Check ARIA attributes - Verify aria-labelledby and aria-describedby reference correct IDs
4. Validate HTML - Ensure the generated SVG is valid

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Next steps