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Mermaid sankey diagram syntax: flows, nodes and values with examples

Mermaid sankey-beta syntax with rendered examples: CSV source,target,value rows, multi-stage flows, quoted node names and weighted ribbons.

A Sankey diagram shows quantities moving between stages: a budget splitting into departments, traffic flowing through a funnel, energy losses through a system. Ribbon width is the value, so the picture is a proportion chart with a direction.

Everything on this page is rendered by makesPDF's own Mermaid renderer, so a ```mermaid block produces exactly this in the PDF.

Rows are CSV

After the sankey-beta header, every line is one link — source,target,value, no spaces around the commas required and no node declarations anywhere:

mermaid
sankey-beta
  Revenue,Salaries,480
  Revenue,Infrastructure,220
  Revenue,Marketing,140
  Revenue,Operations,95
Render this to PDF →How diagram blocks work

Nodes appear in the column their links put them in, and within a column the renderer orders them to keep the ribbons from crossing. The layout is computed from the values, so there is nothing else to configure.

Multiple stages

Chaining rows through an intermediate node gives the diagram depth: the second stage's nodes are placed in a further column and their ribbons fan out from the first:

mermaid
sankey-beta
  Revenue,Salaries,480
  Revenue,Infrastructure,220
  Revenue,Marketing,140
  Salaries,Engineering,260
  Salaries,Sales,120
  Salaries,Management,100
  Infrastructure,Cloud,150
  Infrastructure,Office,70
  Marketing,Ads,90
  Marketing,Events,50
Render this to PDF →How diagram blocks work

Quoted names

A name containing a comma or a space has to be double-quoted. A literal quote inside a quoted name is written twice (""):

mermaid
sankey-beta
  "Annual Budget",Salaries,480
  "Annual Budget","Research & Development",95
  "Annual Budget","Office, facilities",60
  Salaries,"Sales & Support",120
Render this to PDF →How diagram blocks work

Unquoted single-word names work too — quoting is only required when the comma would otherwise split the field.

Repeated pairs

Two rows between the same pair of nodes are summed into one ribbon, which is how a diagram built from per-month rows behaves:

mermaid
sankey-beta
  Signups,Activated,120
  Signups,Activated,80
  Signups,Churned,40
  Activated,Paying,150
  Activated,Dormant,50
Render this to PDF →How diagram blocks work

Signups → Activated draws as 200, the sum of the two rows. Values must be zero or positive numbers; a row with a negative or non-numeric value, or any other row that cannot be parsed, is skipped rather than failing the diagram.

Not supported in makesPDF yet: a link that would create a cycle is dropped (and reported as a layout warning) so the layout cannot loop — restructure the data so flow only moves forward. Node and link styling is not applied, and node labels are drawn beside their column rather than inside the ribbon.