Mermaid Viewer - Online Diagram Editor with Live Preview

Quick Verdict

Mermaid Viewer is a browser-based tool for creating, editing, previewing, and sharing Mermaid diagrams, with templates that can help users get started. It may suit people who want to work with diagram code without setting up a local editor, though privacy practices and the details of paid options are not clearly stated.

Key Features

The editor shows a live preview as you type. The website also describes real-time collaboration and diagram export, but does not clearly list the supported export formats; verify that they fit your workflow before relying on this capability.

A template library offers editable examples, including flowcharts, sequence diagrams, and ER models. Users can browse a template, duplicate it, edit its Mermaid code, and export the result. The library includes free resources as well as premium examples. The online viewer is described as free, but the website does not clearly state specific pricing, plan limits, or premium template costs.

One practical caveat: a listed Governance Committee Decision Flow template had no available preview. That may not reflect the whole library, but it is worth checking individual templates before choosing one. The website does not clearly state how diagram content is handled or what privacy protections apply.

Who this is for

Mermaid Viewer appears suited to business, engineering, and product teams that need to create or adapt diagrams in the browser, as well as individuals who prefer starting from an example rather than a blank editor. It may be less suitable for work involving sensitive diagrams until you verify the service’s data-handling practices. If export formats, collaboration details, or premium costs matter to your decision, verify them on the official website.