Free Online Flowchart Editor

Create professional flowcharts using simple text-based syntax. Instant preview, export to SVG/PNG, and share via URL - all for free.

Start Creating Flowcharts

Key Features

  • Real-time preview as you type
  • Export to SVG or PNG formats
  • Share diagrams via URL
  • No sign-up or installation required
  • Support for decision nodes, processes, and connectors
  • Dark mode support

Common Use Cases

  • Document business processes
  • Visualize algorithms and logic flows
  • Create user journey maps
  • Design system workflows
  • Plan project processes
  • Explain decision trees

Example Flowchart

flowchart TD
    Start([Start]) --> Input[/Enter Data/]
    Input --> Process[Process Data]
    Process --> Decision{Valid?}
    Decision -->|Yes| Save[(Save to DB)]
    Decision -->|No| Error[Show Error]
    Error --> Input
    Save --> Success([Success])
Try this example

Why Use This Flowchart Editor?

Our free online flowchart editor makes it easy to create professional diagrams using simple text-based syntax. No installation required - just start typing and see your diagram render in real-time.

Built on Mermaid.js, this editor provides instant preview, SVG/PNG export, and URL sharing capabilities. Perfect for developers, technical writers, project managers, and anyone who needs to create clear, professional diagrams quickly.

How to Create a Flowchart with Mermaid

  1. Start with the flowchart keyword and orientation (TD for top-down, LR for left-right)
  2. Define nodes with unique IDs and labels using different bracket types for different shapes
  3. Connect nodes with arrows using --> for standard flow or other arrow types for different relationships
  4. Add decision points using diamond shapes {text} to represent conditional logic
  5. Use special node types like ([rounded]) for start/end, [(database)] for storage, or [/input output/] for I/O operations
  6. Test your diagram in the preview pane and adjust the layout as needed
  7. Export your completed flowchart as SVG for scalability or PNG for quick sharing

Best Practices for Flowchart Design

  • Keep it simple: Use clear, concise labels that describe each step or decision accurately
  • Maintain consistent direction: Stick to one primary flow direction (top-to-bottom or left-to-right) throughout your diagram
  • Use standard shapes: Follow conventional flowchart symbols - rectangles for processes, diamonds for decisions, ovals for start/end
  • Limit complexity: If your flowchart becomes too complex, consider breaking it into multiple smaller diagrams
  • Add clear decision paths: Label all paths from decision nodes with 'Yes/No' or specific conditions
  • Group related processes: Use subgraphs or visual spacing to organize related steps together
  • Test the logic: Walk through your flowchart from start to finish to ensure all paths make sense
  • Consider your audience: Adjust the level of detail based on who will be reading the flowchart

Advanced Flowchart Features

Subgraphs for Grouping

Use subgraph blocks to visually group related processes or create swimlanes for different departments or systems. This helps organize complex workflows and shows responsibility boundaries.

Styling Individual Nodes

Apply custom CSS classes to highlight important nodes, color-code by type, or emphasize critical paths. Use the classDef and class keywords to define and apply custom styles.

Multiple Arrow Types

Mermaid supports various arrow types including dotted lines (-.->), thick lines (==>), and open arrows (-.->) to represent different relationship types like optional flows, data flows, or subprocess calls.

Interactive Links

Add clickable URLs to nodes for documentation linking or navigation to related resources. Perfect for creating interactive documentation that connects to detailed specifications.

Common Mistakes to Avoid

  • ⚠️Using inconsistent node IDs - each node must have a unique identifier that doesn't change
  • ⚠️Forgetting to close brackets properly - each node shape requires matching opening and closing brackets
  • ⚠️Creating infinite loops without exit conditions - ensure all loops have a way to exit
  • ⚠️Overcomplicating the diagram - if you need more than 15-20 nodes, consider splitting into multiple flowcharts
  • ⚠️Using unclear arrow labels - always label decision branches clearly with conditions or Yes/No
  • ⚠️Mixing flowchart styles - stick to one notation system (Mermaid, BPMN, etc.) throughout
  • ⚠️Neglecting edge cases - make sure to account for error conditions and alternative paths
  • ⚠️Poor node naming - use descriptive IDs and labels that make the flowchart self-documenting

When to Use Flowcharts vs Other Diagram Types

Flowcharts are ideal for representing sequential processes, decision logic, and workflows with clear steps. Use flowcharts when you need to document standard operating procedures, explain algorithms, or map out user journeys.

Choose sequence diagrams instead when focusing on interactions between different actors or systems over time. Use state diagrams when modeling the different states an object can be in and transitions between those states. For organizational structures or class relationships, class diagrams are more appropriate.

The key advantage of flowcharts is their universal understanding - they use standard symbols that are recognized across industries and don't require technical knowledge to interpret. This makes them excellent for business process documentation, training materials, and stakeholder communication.

Frequently Asked Questions

Common questions about using the Mermaid Viewer and creating diagrams