Top 10 Best Mermaid Diagram Online Software of 2026

Miro bridges code-based diagramming and visual collaboration: paste Mermaid code into a board, start from a template, or use an MCP client to create, update, or read a diagram. Rendered diagrams become editable shapes, so teammates can make visual adjustments without editing Mermaid code, while standard syntax stays available for export, versioning, diffs, and pull-request review.

This approach fits engineering teams reviewing flows with product managers or clients, since collaborators can see and comment on the same live diagram rather than a stale screenshot. The tradeoff is that Miro is centered on shared visual work; teams whose main task is automated, build-time diagram rendering may prefer a repository-focused renderer.

Excalidraw converts Mermaid diagrams into editable shapes rather than leaving them as static images. Users can adjust elements on the canvas, add annotations, and share a collaboration room for live edits. The React package and API provide an integration path for teams embedding a drawing surface in their own applications.

Converted diagrams do not remain linked to their original Mermaid source, so later syntax changes require another conversion. Excalidraw fits a product team that wants to turn a flowchart draft into a shareable, hand-drawn explainer, but it offers less control for maintaining a source-driven diagram library.

Eraser pairs a diagram-as-code editor with a canvas, so technical teams can work from text or adjust diagrams visually. Its supported diagram types include flowcharts, sequence diagrams, entity-relationship diagrams, and cloud architecture diagrams. Team collaboration and image exports support documentation workflows.

Eraser uses its own diagram syntax rather than native Mermaid syntax, so teams maintaining Mermaid source may need to convert or rewrite diagrams. It suits engineering teams creating architecture diagrams for shared technical documentation.

Diagram-as-code workflows favor editable source over canvas manipulation, and D2 turns text definitions into rendered diagrams in an online playground or local CLI. Its language supports labeled connections, containers, styling, and reusable diagram elements.

Mermaid Live Editor converts Mermaid text definitions into diagrams in a browser, pairing a code editor with a live preview. It supports flowcharts, sequence diagrams, class diagrams, entity-relationship diagrams, Gantt charts, and other Mermaid diagram types.

For teams documenting architecture alongside technical notes, HackMD pairs a real-time Markdown editor with Mermaid rendering in the same workspace. Collaborators can edit notes together, control sharing, and publish documentation or slide decks.

Mermaid Chart pairs Mermaid's text-based diagram syntax with a visual editor, unlike canvas-first tools built around manual shape placement. It supports flowcharts, sequence diagrams, class diagrams, entity-relationship diagrams, and Gantt charts, with shared editing and export options.

Among online diagram editors, diagrams.net combines Mermaid rendering with a broad canvas for flowcharts, network maps, UML, and other diagram types. Users can enter Mermaid syntax and insert the result as an SVG or convert it into editable diagram shapes.

Drawio converts Mermaid text into diagrams inside a browser-based editor for flowcharts, UML, network maps, BPMN, and architecture layouts. Mermaid output can be inserted as an image or converted into editable Drawio shapes, though shape conversion may not retain every source-level detail.

Markdown Preview Mermaid Support fits developers who write Markdown in Visual Studio Code and need diagrams shown alongside their documentation. Its distinction is focused: it adds Mermaid rendering to VS Code's built-in Markdown preview rather than providing a standalone online diagram editor.