Top 10 Best Mermaid Online Software of 2026

Miro lets users paste Mermaid code onto a board and automatically render it as editable shapes, or start from a diagram template. Teams can comment on diagrams and make visual edits on the canvas, while standard Mermaid syntax keeps edits exportable for versioning, diffs, and pull-request review. MCP support also connects diagram workflows with tools such as Claude Code, Cursor, and other MCP clients.

The tradeoff is that Miro pairs code-based diagramming with a collaborative canvas rather than focusing solely on editing Mermaid source in a code editor. It fits a design review where engineers map an application flow and then share an editable visual with a manager or client.

Excalidraw suits teams that prefer arranging diagram elements visually over writing diagram code. Its scene data can be saved as JSON, and its JavaScript package exposes drawing functionality for embedding in applications. Shared rooms support live collaboration on the same canvas.

Excalidraw does not render Mermaid syntax, so existing Mermaid text diagrams cannot be edited as native diagrams on its canvas. It fits workshops where participants need to sketch a flow together and export an image for documentation.

Eraser supports Mermaid diagrams as well as its own diagram-as-code workflow, with visual editing for flowcharts, sequence diagrams, entity-relationship diagrams, and cloud architectures. Teams can keep diagrams beside explanatory documents in shared workspaces and export visuals for other documentation.

The broader workspace adds canvas and document controls that a code-only Mermaid renderer does not need, and visual editing can require layout adjustments to diagrams. Eraser suits engineering groups documenting service flows and architecture together, but is less suited to users who only need a lightweight Mermaid preview.

Among browser-based diagram editors, Diagrams.net combines a flexible canvas with direct Mermaid source insertion. Its Mermaid workflow renders source as editable diagram elements or an SVG image, alongside native flowchart, UML, network, and architecture shapes.

Gliffy creates flowcharts, UML diagrams, network maps, and wireframes on a drag-and-drop canvas rather than through Mermaid-style text syntax. Shape libraries, connectors, and templates support common diagram types and make visual editing accessible to teams.

Whimsical suits product and engineering teams that want to turn Mermaid diagrams into editable visuals alongside planning work. Mermaid import sits alongside flowcharts, mind maps, wireframes, and collaborative docs.

Terrastruct differs from Mermaid-first editors by pairing a visual diagram workspace with D2, a text-based language for software architecture diagrams. Layers and scenarios let teams represent alternate system states without duplicating an entire diagram. D2 syntax is the native editing format, so Mermaid users need to adapt existing diagram source before using Terrastruct's code workflow.

In browser-based diagramming, Lucidchart pairs broad diagram libraries with real-time team editing. Templates and shape libraries cover flowcharts, BPMN, UML, ER diagrams, network maps, and organizational charts. Data linking, revision history, and integrations with Google Workspace, Microsoft 365, Atlassian, and Slack support shared documentation workflows.

Mermaid Live Editor converts Mermaid text into diagrams with a live preview beside the code editor. It supports many Mermaid diagram types, including flowcharts, sequence diagrams, class diagrams, and entity-relationship diagrams.

PlantUML Web Server suits developers who want diagrams rendered from text, distinguishing itself from Mermaid editors by using PlantUML syntax rather than Mermaid syntax. Its browser form and HTTP endpoints convert source into PNG or SVG images, while encoded diagram URLs support linking and embedding. PlantUML supports sequence, class, activity, component, and deployment diagrams, but the server focuses on rendering rather than shared visual editing.