Graphviz Diagram Generator

Generate diagrams from natural language descriptions and return a clickable link to GraphvizOnline with the rendered preview.

When to Use

• "Draw the architecture of ..."
• "Make a diagram showing ..."
• "Visualize the data flow between ..."
• "Create a flowchart for ..."
• "Show dependencies between ..."
• "State machine diagram for ..."
• "ER diagram of ..."
• Any request involving diagrams, graphs, schemas, architecture visualization

Workflow

1. If the user's description is vague, ask one clarifying question before generating
2. Generate valid DOT code following the conventions below
3. Show the DOT code in a fenced ```dot block
4. Construct the URL: https://dreampuf.github.io/GraphvizOnline/# + URL-encoded DOT code
5. Output the link on its own line so it's clickable

DOT Code Conventions

Graph type

• digraph for directed graphs (architecture, flows, dependencies, state machines)
• graph for undirected graphs (relationships, peer networks)

Layout direction

• rankdir=LR for wide/horizontal layouts (architecture, pipelines)
• rankdir=TB for tall/vertical layouts (flowcharts, hierarchies)

Node shapes by component type

• box or component -- services, applications, modules
• cylinder -- databases, storage
• ellipse -- users, actors, external systems
• diamond -- decision points (flowcharts)
• folder -- directories, namespaces, packages
• note -- annotations, comments
• record -- structured data, ER entities (use <field> syntax for fields)
• doublecircle -- start/end states (state machines)
• circle -- intermediate states

Grouping

• Use subgraph cluster_name { label="Group Name"; ... } to group related components
• Give clusters a light fill: style=filled; color=lightgrey;

Styling

• Use fontname="Helvetica" on the graph for clean rendering
• Color-code edges or nodes to distinguish component types when helpful
• Keep labels concise -- full names on nodes, short verbs on edges
• Use style=dashed for optional or async connections

Edges

• Label edges with the relationship or protocol: -> with [label="HTTP"], [label="gRPC"], [label="publishes"]
• Use style=dashed for async/optional connections
• Use dir=both for bidirectional relationships

URL Construction

Construct the GraphvizOnline URL by URL-encoding the entire DOT source and appending it as a hash fragment:

https://dreampuf.github.io/GraphvizOnline/#<URL-encoded DOT code>

The DOT code must be encoded with standard percent-encoding (spaces -> %20, newlines -> %0A, etc.).

Output Format

Always output in this order:

1. Brief description of what the diagram shows (1 sentence)
2. The DOT source in a fenced ```dot block
3. The clickable GraphvizOnline link on its own line

Example output structure:

Architecture showing the API gateway routing to backend services:

digraph { ... }

Open in GraphvizOnline