Mermaid Editor

Online Mermaid Diagram Editor with Live Preview

PlainRaw's Mermaid editor turns a few lines of plain-text syntax into a clean SVG diagram, updated as you type. No installs, no plugins — just write Mermaid code and watch the diagram render next to it.

Supported diagram types

  • Flowcharts for processes, decision trees, and architecture sketches.
  • Sequence diagrams for documenting request flows between services or actors.
  • Class diagrams for outlining object models and relationships.
  • State diagrams for finite state machines and lifecycle transitions.
  • Entity-Relationship diagrams for database schemas and data models.

Why edit Mermaid online?

Diagram-as-code keeps your visuals in version control and easy to review, but iterating locally usually means installing a plugin or running a build. With this editor you can prototype a diagram in seconds, copy the source into a Markdown document, or save it as a snippet and share the link with a teammate. The preview rerenders on every keystroke, so you can fine-tune labels and arrows without round-trips through a build pipeline.