Diagram Generator
AI-powered diagram creation, editing, and format conversion from your terminal. Generate flowcharts, sequence diagrams, ER diagrams, architecture diagrams and more in Mermaid, draw.io, PlantUML, and Graphviz formats.
Powered by Evolink.ai
When to Use
- User wants to generate a diagram from a natural language description
- User asks to modify or update an existing diagram file
- User needs to convert a diagram between formats (e.g., Mermaid to draw.io)
- User wants to understand what an existing diagram represents
- User asks to preview or render a diagram locally
- User needs a quick reference for diagram types and format syntax
Quick Start
1. Set your EvoLink API key
export EVOLINK_API_KEY="your-key-here"
Get a free key: evolink.ai/signup
2. Generate a diagram
bash scripts/diagram.sh generate flowchart "user login flow with OAuth and MFA"
3. Preview it
bash scripts/diagram.sh preview login_diagram.mmd
Capabilities
Local Commands (no API key needed)
| Command | Description |
|---|---|
templates |
List all diagram types, formats, and usage examples |
preview <file> |
Open diagram in browser (Mermaid HTML, draw.io link, PlantUML URL, Graphviz SVG) |
AI Commands (require EVOLINK_API_KEY)
| Command | Description |
|---|---|
generate <type> [--format <fmt>] "<desc>" |
AI generate diagram from natural language description |
edit <file> "<instruction>" |
AI modify existing diagram file based on instruction |
convert <file> --to <format> |
AI convert diagram between formats |
explain <file> |
AI explain diagram structure in plain language |
Diagram Types
| Type | Description |
|---|---|
flowchart |
Process flows, decision trees, workflows |
sequence |
API calls, service interactions, message flows |
class |
OOP class hierarchies, interfaces, relationships |
er |
Database entity-relationship diagrams |
state |
State machines, lifecycle transitions |
mindmap |
Idea maps, topic hierarchies, brainstorming |
architecture |
System architecture, microservices, cloud infra |
network |
Network topology, server layout, connectivity |
gantt |
Project timelines, task scheduling |
pie |
Data distribution, proportions |
git |
Git branch/merge visualization |
c4 |
C4 model (context, container, component, code) |
Output Formats
| Format | Extension | Best For |
|---|---|---|
mermaid |
.mmd |
Documentation, README files (native GitHub/GitLab rendering) |
drawio |
.drawio |
Architecture diagrams (drag-and-drop editing in diagrams.net) |
plantuml |
.puml |
UML diagrams (rich UML support, sequence diagrams) |
graphviz |
.dot |
Graph/network layouts (automatic layout algorithms) |
Examples
Generate a flowchart
bash scripts/diagram.sh generate flowchart "CI/CD pipeline with build, test, and deploy stages"
Generate an ER diagram in draw.io format
bash scripts/diagram.sh generate er --format drawio "e-commerce database with users, orders, products"
Edit an existing diagram
bash scripts/diagram.sh edit flow.mmd "add error handling branch after validation step"
Convert Mermaid to draw.io
bash scripts/diagram.sh convert flow.mmd --to drawio
Explain a diagram
bash scripts/diagram.sh explain architecture.puml
Preview a Mermaid diagram
bash scripts/diagram.sh preview flow.mmd
Configuration
| Variable | Default | Required | Description |
|---|---|---|---|
EVOLINK_API_KEY |
— | Yes (AI commands) | Your EvoLink API key. Get one free |
EVOLINK_MODEL |
claude-opus-4-6 |
No | Model for AI generation |
Required binaries: python3, curl
Optional: dot (Graphviz) for local SVG rendering in preview command
Security
Data Transmission
AI commands send diagram content to api.evolink.ai for processing by Claude. By setting EVOLINK_API_KEY and using these commands, you consent to this transmission. Data is not stored after the response is returned. The templates and preview commands run entirely locally and never transmit data.
Preview Command
- Mermaid preview generates a local HTML file using the Mermaid.js CDN — no diagram data is sent externally.
- PlantUML preview sends diagram code to
plantuml.comfor rendering. A warning is displayed before opening. - draw.io preview opens the diagrams.net web app — you load the file manually.
- Graphviz preview renders locally via the
dotbinary if installed.
Network Access
api.evolink.ai— AI generation (AI commands only)cdn.jsdelivr.net— Mermaid.js library (preview command, Mermaid format only)plantuml.com— PlantUML rendering (preview command, PlantUML format only)
Persistence & Privilege
Temporary files for API payloads are cleaned up automatically. No credentials or persistent data are stored.