architecture-diagram-generator

name

architecture-diagram-generator

description

Generates architecture diagrams as Mermaid code from system descriptions, service lists, or existing documentation. Supports flowcharts, sequence diagrams, entity-relationship diagrams, and C4 context diagrams. Use this skill whenever a user says "draw an architecture diagram", "create a Mermaid diagram for this", "diagram this system", "show me a sequence diagram for this flow", "generate an ERD for these tables", "visualize this API flow", "draw the data flow for this", or "make a diagram of how these services connect". Also activate when a user describes a system and wants it visualized. Do NOT use for creating actual architecture (use system-design approaches), generating image files directly, or creating UI wireframes.

Architecture Diagram Generator

Generate clear, readable Mermaid diagrams for system architectures, service dependencies, API flows, and data models — ready to paste into Notion, GitHub, or any Markdown renderer.

When to Use

• Documenting how services connect in a system
• Visualizing API request/response flows
• Drawing ERDs for database schemas
• Creating C4 context diagrams for documentation
• Showing data pipelines or workflow sequences

When NOT to Use

• Designing the architecture itself (this is a visualization skill)
• Generating image files (.png, .svg) — Mermaid renders in Markdown viewers
• UI wireframes or screen mockups

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Workflow

Step 1 — Understand the Diagram Need

Ask the user:

1. What to diagram: System overview / API flow / Data model / Workflow / Service map
2. Diagram type: Flowchart / Sequence / ERD / C4 / Class / State machine / Gantt
3. Level of detail: High-level overview vs. detailed with all fields/methods
4. Components involved: List of services, tables, actors, or steps

Step 2 — Select the Right Diagram Type

Use case	Mermaid type
Service topology / system overview	flowchart LR or flowchart TD
API or event sequence	sequenceDiagram
Database tables and relationships	erDiagram
System context / C4	C4Context
Deployment / infrastructure	flowchart with styled nodes
State machine	stateDiagram-v2
Process / workflow steps	flowchart TD
Project timeline	gantt

Step 3 — Generate the Mermaid Code

System Architecture (Flowchart)

flowchart LR
    Client["🖥️ Web Client"]
    LB["Load Balancer"]
    API["API Server\n(Node.js)"]
    Auth["Auth Service"]
    DB[("PostgreSQL")]
    Cache[("Redis Cache")]
    Queue["Message Queue\n(RabbitMQ)"]
    Worker["Background Worker"]

    Client --> LB
    LB --> API
    API --> Auth
    API --> DB
    API --> Cache
    API --> Queue
    Queue --> Worker
    Worker --> DB

API Sequence Diagram

sequenceDiagram
    actor User
    participant App
    participant AuthService
    participant Database

    User->>App: POST /login {email, password}
    App->>AuthService: ValidateCredentials(email, password)
    AuthService->>Database: SELECT user WHERE email=?
    Database-->>AuthService: User record
    AuthService-->>App: JWT token
    App-->>User: 200 OK {token, expiresAt}

Entity-Relationship Diagram

erDiagram
    USER {
        uuid id PK
        string email UK
        string full_name
        timestamp created_at
    }
    ORDER {
        uuid id PK
        uuid user_id FK
        decimal amount
        string status
        timestamp created_at
    }
    ORDER_ITEM {
        uuid id PK
        uuid order_id FK
        uuid product_id FK
        int quantity
        decimal unit_price
    }

    USER ||--o{ ORDER : "places"
    ORDER ||--|{ ORDER_ITEM : "contains"

Step 4 — Apply Styling (Optional)

For flowcharts, add node styles for visual clarity:

flowchart TD
    API["API Server"]
    DB[("Database")]
    
    style API fill:#4A90D9,color:#fff
    style DB fill:#7B7B7B,color:#fff

Step 5 — Present and Iterate

Show the diagram code and note:

• "This renders in GitHub Markdown, Notion, GitLab, and most Markdown editors."
• "Tip: Use Mermaid Live Editor to preview."

Ask: "Should I add more detail, change the direction, or adjust any components?"

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Output Format

A Mermaid code block with:

1. The diagram type declaration on the first line
2. Clean, readable node IDs (not random letters)
3. Descriptive labels using quotes for multi-word/special character names
4. Grouping related nodes with subgraph where helpful

Include a brief explanation of what the diagram shows and any key relationships to note.

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Safety & Confirmation

• Don't include real hostnames, IP addresses, or internal service names unless the user explicitly provides them for documentation.
• For sequence diagrams showing auth flows, note any security concerns you observe (e.g., token passed in query string).
• Verify the diagram is syntactically valid Mermaid before presenting (review brackets, arrows, quoting).