Flowchart generator online uses Mermaid syntax to turn plain text descriptions into clean, rendered diagrams instantly. Define your nodes and connections in simple markup and see the flowchart appear in real time with no signup or software required. This free browser-based tool is useful for documenting processes, planning application logic, and visualizing decision trees.
The Mermaid Diagram Generator lets you write Mermaid diagram syntax and see the rendered diagram in real time in a side-by-side preview. Mermaid is a text-based diagramming language that generates flowcharts, sequence diagrams, class diagrams, Gantt charts, entity-relationship diagrams, pie charts, and more from plain text definitions. It is supported natively by GitHub and GitLab Markdown, Notion, Confluence, and many documentation tools. Writing diagrams as text rather than drawing them manually has several advantages: diagrams can be stored in version control, reviewed in pull requests, generated programmatically, and updated by editing text rather than rearranging shapes. This tool provides real-time rendering, a syntax reference panel, and multiple diagram examples to help you get started.
Mermaid syntax is designed to be readable as text even without rendering. A simple flowchart looks like: graph TD; A[Start] --> B{Decision}; B -->|Yes| C[Action]; B -->|No| D[End]. The indentation and arrow notation makes the structure clear even in raw text form. Sequence diagrams use participant and actor declarations followed by arrows (->>, -->>) to show message flow between components, which is ideal for documenting API call sequences, authentication flows, and event-driven systems. Class diagrams support inheritance, composition, and interface implementation, which is useful for documenting object-oriented system designs. Gantt charts display project timelines with tasks and dependencies. Entity-relationship diagrams document database schemas. For technical documentation in GitHub repositories, Mermaid code blocks (triple backtick followed by "mermaid") render automatically in Markdown files, README files, and GitHub Wiki pages without any plugins. For Confluence, a dedicated Mermaid macro or the built-in Markdown renderer supports it. When embedding in web pages, the mermaid.js library (available from CDN) renders diagrams client-side from script tags with type="text/x-mermaid". This tool is particularly useful for previewing and iterating on diagram syntax before embedding it in documentation.