graphviz

Graphviz DOT Diagram Generator

Important: Use ```dot as the code fence identifier, NOT ```graphviz.

Quick Start: Choose digraph (directed) or graph (undirected) → Define nodes with attributes (shape, color, label) → Connect with -> or -- → Set layout (rankdir, spacing) → Wrap in ```dot fence. Default: top-to-bottom (rankdir=TB), cluster names must start with cluster_, use semicolons.

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Critical Syntax Rules

Rule 1: Cluster Naming

❌ subgraph backend { }      → Won't render as box
✅ subgraph cluster_backend { }  → Must start with cluster_

Rule 2: Node IDs with Spaces

❌ API Gateway [label="API"];    → Invalid ID
✅ "API Gateway" [label="API"];  → Quote the ID
✅ api_gateway [label="API Gateway"];  → Use underscore ID

Rule 3: Edge Syntax Difference

digraph: A -> B;   → Directed arrow
graph:   A -- B;   → Undirected line

Rule 4: Attribute Syntax

❌ node [shape=box color=red]    → Missing comma
✅ node [shape=box, color=red];  → Comma separated

Rule 5: HTML Labels

✅ shape=plaintext for HTML labels
✅ Use < > not " " for HTML content

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Common Pitfalls

Issue	Solution
Nodes overlapping	Increase nodesep and ranksep
Poor layout	Change rankdir or add {rank=same}
Edges crossing	Use splines=ortho or adjust node order
Cluster not showing	Name must start with cluster_
Label not displaying	Check quote escaping

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Output Format

```dot
digraph G {
    [diagram code]
}
```

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Related Files

For advanced layout control and complex styling, refer to references below:

• syntax.md — Layout control (rankdir, splines, rank), HTML labels, edge styles, cluster subgraphs, and record-based nodes