Free live Mermaid diagram editor with no signup required
A native Mac editor for text, CSVs, and data files
Stage
Not given
Not given
Founded
Not given
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Based in
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US
Pricing model
Free
Freemium
Pricing
Not given
Caxton Free (free forever); Caxton Pro monthly at $9.99 USD, annual at $99.99 USD, or lifetime at $179.99 USD. Team pricing starts at $79 to $99.99 USD per seat per year.
Key features
Live preview as you type
21 diagram types including flowcharts, sequence, class, state, ER, Gantt, git graph, mindmap and timeline
Two-way editing for flowcharts
SVG and PNG export
Share diagrams as URLs with embedded diagram content
Built-in template picker and cheatsheet
No account or signup required
Works entirely in browser with local storage
Open Mermaid Live Editor links
Mermaid v11 syntax support
Text editing with memory-mapped files for large documents
CSV and TSV table editing with column transforms
Column transformations and data type preservation
CSV validation with structural and data rules
File comparison without copying data
Extract matches and columns to new documents
Local processing with no cloud uploads or telemetry
What makes it different
No signup, paywall, or data collection required
Diagrams stay in your browser's local storage by default
Two-way editing that updates code when you edit the canvas
Live preview with no render button required
Clean SVG export for professional use in docs and slides
Opens files directly from disk without importing or uploading, preserving data exactly as stored
Combines text editor, CSV table editor, and log viewer in one native Mac application
Handles multi-gigabyte files with consistent performance and one-millisecond keystroke latency
Preserves leading zeros, long IDs, and data types exactly as stored in the file
All files stay local to your Mac with no cloud processing, telemetry, or vendor lock-in
FlowViz
Caxton