# Mermaid Viewer

Free online Mermaid viewer. Open and preview Mermaid diagrams (.mermaid, .mmd) directly in your browser — no upload, no software.

> Canonical page: https://elysiatools.com/en/viewers/mermaid

- **Category:** Diagrams

- **Supported formats:** .mermaid, .mmd

## Overview

This Mermaid viewer renders Mermaid text-based diagrams directly in your browser. Mermaid (.mermaid, .mmd) lets you create flowcharts, sequence diagrams, Gantt charts and more using simple text syntax — no drawing required. Pick a sample diagram or choose your own .mermaid / .mmd file to preview it instantly, with no upload.

## When to use

- You received a .mermaid or .mmd file and want to render it visually.
- You need a quick, private preview of a text-based diagram.
- You want to check a Mermaid chart embedded in documentation.

## How it works

- Select a built-in sample diagram or choose your own .mermaid / .mmd file.
- The viewer parses the Mermaid syntax and renders the diagram using the Mermaid.js library in your browser — nothing is uploaded.
- Pan and zoom to inspect the rendered diagram.

## Use cases

- Rendering flowcharts from Markdown documentation.
- Previewing sequence and Gantt diagrams.
- Checking Mermaid charts from GitHub and GitLab.

## Samples

- **Sample Mermaid Diagram**: A Mermaid diagram sample for in-browser preview

## Frequently asked questions

### What is a Mermaid file?

Mermaid (.mermaid, .mmd) is a text-based diagramming format that uses simple markdown-like syntax to generate flowcharts, sequence diagrams, Gantt charts, class diagrams, state diagrams and more. It is supported natively by GitHub, GitLab, Notion and many documentation tools.

### Are my Mermaid files uploaded?

No. Diagrams you open from your device stay on your device and are rendered locally with Mermaid.js. Only the public sample diagram is requested from the server.

### What diagram types does Mermaid support?

Mermaid supports flowcharts, sequence diagrams, class diagrams, state diagrams, entity relationship diagrams, Gantt charts, pie charts, journey maps, mind maps and timelines — all from text syntax.

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