Mermaid from data
Paste edges, optional node metadata and relationship styles, then generate Mermaid source for flowcharts, class diagrams or ER diagrams.
About this tool
Mermaid from data turns the rows you already have into paste-ready Mermaid diagram source. Use arrow lines like Start -> Build : work, delimited edge rows like from,to,label,style, or chain rows like Draft,Review,Ship. Optional node rows add friendly labels, flowchart shapes, subgraph groups, class members or ER attributes.
The output is plain Mermaid text, so you can paste it into Markdown, docs sites, issue trackers or any renderer that supports Mermaid. The generator does not render images; it focuses on producing readable, deterministic source that can be reviewed and version-controlled.
Example: a short left-to-right flowchart from arrow lines:
gizza tool mermaid-from-data edges="Start -> Build : implement
Build -> Ship : deploy" direction=LR title="Release pipeline"
For tabular input, use row_mode=pair when each row is from,to,label,style, or row_mode=chain when each row is a path and adjacent columns should be linked.
Limits and edge cases
- Up to 500 nodes, 1000 edges and 2 MB each for edges and node declarations.
- Flowcharts support node shapes, subgraph groups and arrow/open/dotted/thick/bidirectional edge styles.
- Class diagrams map relationship styles such as inheritance, composition, aggregation and dependency to Mermaid operators.
- ER diagrams map common cardinality names such as one-to-many and one-to-one-or-more.
- Node identifiers are sanitized for Mermaid while labels preserve the original text.
FAQ
Can I paste CSV directly?
Yes. Set delimiter to comma or leave it on auto for simple CSV-style rows. A header row such as from,to,label,style is skipped automatically, and quoted fields keep commas inside the label.
What is the difference between pair mode and chain mode?
Pair mode treats each row as one edge: source, target, optional label and optional style. Chain mode treats each row as a path, so Draft,Review,Publish becomes Draft --> Review and Review --> Publish.
Does this validate Mermaid rendering?
It validates the structured data and emits Mermaid source, but it does not run a browser renderer or catch every Mermaid syntax rule. Paste the output into your Mermaid renderer for final visual layout checks.
How do I add class members or ER attributes?
Use the node declarations field. For a class diagram, write rows such as Animal | +String name; +eat(). For an ER diagram, write rows such as CUSTOMER | string name PK; string email.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool mermaid-from-data "Start -> Build : implement
Build -> Ship : deploy"New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/mermaid-from-data/?edges=Start%20-%3E%20Build%20%3A%20implement%0ABuild%20-%3E%20Ship%20%3A%20deploy&nodes=api%20%7C%20API%20service%20%7C%20round%20%7C%20Backend%0Adb%20%7C%20Postgres%20%7C%20cylinder%20%7C%20Backend&diagram=flowchart&direction=TD&row_mode=pair&delimiter=auto&node_shape=rect&edge_style=arrow&title=Release%20pipeline&fence=trueMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.