Command line

mermaidx -i INPUT -o OUTPUT [options]

Without -o, the SVG is written to standard output. Use -i - to read the diagram from standard input.

The output format comes from the extension of -o: .svg, .png, .jpg, .jpeg, .bmp, .tga or .pdf.

Option	Description
-i, --input FILE	Mermaid source file, or - for standard input
-o, --output FILE	Output file. Omit it to write SVG to standard output
--backend NAME	Rendering backend, quickjs by default
--list-backends	List the available backends and exit
-w, --width N	Output width in pixels (PNG, and PDF when fitting)
-H, --height N	Output height in pixels
--scale N	Size multiplier, used when -w and -H are omitted
-t, --theme NAME	default, forest, dark or neutral
-b, --background COLOR	CSS background color, transparent by default
-c, --config FILE	Mermaid JSON config (quickjs and v8 only)
--css FILE	CSS file to inject into the diagram (quickjs and v8 only)
--quality N	JPEG quality from 1 to 100, 90 by default
--pdf-format FORMAT	Paper format such as A4 or Letter; the default fits the diagram
--landscape	Landscape orientation, PDF only
--margin MARGIN	PDF margin such as 1cm, 0 by default
-q, --quiet	Hide informational messages
--info	Print the Mermaid library version and exit
--version, -v	Print the mermaidx version and exit

JPEG has no transparency, so the background is white unless you pass -b.

Examples

mermaidx -i flow.mmd -o flow.png --scale 2 -b white
mermaidx -i flow.mmd -o flow.pdf --pdf-format A4 --margin 1cm
mermaidx -i flow.mmd -o flow.jpg --quality 80
mermaidx -i flow.mmd --backend v8 -o flow.svg