Mermaid Flowchart Examples

The definitive library of professional Mermaid flowchart templates. Visualize system architectures, logic gates, and business processes using our copy-paste ready code snippets.

Why Use Mermaid for Flowcharts?

Flowcharts are the cornerstone of technical communication. Whether you're an architect mapping out a cloud infrastructure or a developer explaining a complex conditional loop, a visual map is always more effective than a block of text. Mermaid.js has revolutionized this by allowing us to treat our diagrams like code.

By using our Mermaid flowchart examples, you can maintain your documentation directly within your Markdown files and Git repositories. This "Documentation as Code" approach ensures that your visuals never go out of date and are easily searchable, diffable, and versionable.

1. Simple Decision Logic

A foundational template for handling conditional workflows and standard "If/Else" logic.

graph TD
  A[Start] --> B{Is it raining?}
  B -- Yes --> C[Take Umbrella]
  B -- No --> D[Wear Sunglasses]
  C --> E[Go Outside]
  D --> E[Go Outside]
Live Rendering

2. Auth & API Flow

Visualize secure data interactions using specific node styling and subgraphs.

graph LR
  subgraph Client
    A[UI] --> B[Auth Hook]
  end
  subgraph Server
    B -->|Token| C[API Gateway]
    C --> D[Microservice]
  end
  D -->|Data| B
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3. Retry Strategy

A complex loop structure showing a 3-tier retry policy for distributed systems.

graph TD
  Start --> Call[API Call]
  Call --> Success{Success?}
  Success -- Yes --> End[Finish]
  Success -- No --> Retry[Attempt < 3?]
  Retry -- Yes --> Wait[Wait 2s]
  Wait --> Call
  Retry -- No --> Failure[Error Log]
Live Rendering

How to Optimize Your Mermaid Flowcharts

Choosing Between Directional Orientations

The two most common directions used in our online flowchart maker templates are TD (Top Down) and LR (Left to Right). Choosing the right one is critical for readability:

  • TD (Top-Down): Best for process hierarchies and simple logical flows where the end result is at the bottom.
  • LR (Left-Right): Ideal for time-based processes, user journeys, or infrastructure diagrams where data moves through multiple layers (e.g., Load Balancer → Server → Database).

Leveraging Subgraphs for Complexity

When building large-scale architecture maps, subgraphs are your best friend. They allow you to group related nodes (like all services within a VPC or all logic within a specific class). In the Mermaid flowchart examples above, you can see how subgraphs create a logical separation that makes dense diagrams much easier to digest.

Interactive Diagramming Tips

Did you know that Mermaid flowcharts support styling via CSS? You can use the classDef keyword to create custom styles for error nodes, success nodes, or specific actor types. This level of customization ensures that your mermaid diagram generator output matches your project's branding perfectly.

Ready to Build Your Own?

Take these templates and tweak them to your heart's content in our high-performance editor.

Open Flowchart Editor