Where is the step-by-step Mermaid tutorial?

https://webstatus.in/education/how-to-use-mermaid-diagram-editor — open it from the Guide button in the editor or bookmark it for syntax walkthroughs.

What if I use multiple browser tabs?

The editor keeps one live diagram per browser profile for this origin—tabs share the same local storage. Use named snapshots or separate share links to juggle different diagrams; for isolation, use another browser profile or device.

Is this Mermaid editor free?

Yes. WebStatus.in offers this tool at no charge with no account required.

Does my diagram text leave my browser?

Rendering and SVG export are local. Share links deliberately transmit or encode your diagram for others to open. Short-link creation may store an encrypted payload server-side with TTL; long links can keep data in the URL fragment instead.

Which diagram types are supported?

The bundled Mermaid library supports many types beyond flowcharts—sequence, state, class, Gantt, pie, and others. Unsupported syntax or experimental keywords surface as parser errors in the preview until you adjust the definition.

Can I export to PNG or SVG?

SVG export downloads the last good render. PNG draws the SVG to a canvas in your browser (white background, 2x scaling). Very large diagrams may fail PNG export when canvas size limits are hit; use SVG for maximum fidelity.

Why does the preview update after a short delay?

The tool debounces rendering so typing stays smooth. Pause briefly to see the latest diagram; continuous typing batches updates into one parse pass.

What files can I import?

Use Import to load .mmd, .txt, or plain-text files (including Markdown that contains only a Mermaid block if you paste the relevant lines). Binary formats are not supported.

What does securityLevel strict mean here?

Mermaid is initialized with strict security so diagram code cannot escalate into unsafe HTML execution in the preview. If a feature you expect is blocked, check Mermaid documentation for strict mode compatibility.

How accurate are the results?

Output reflects the Mermaid version locked in our build. For regulated or contractual diagrams, validate in your own CI or desktop toolchain before publication.

Free Mermaid Diagram Editor Online — Flowcharts & Sequence Diagrams

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What is Mermaid?

Mermaid is a text-based diagram language. You author diagrams as plain text (for example a flowchart or a sequence diagram), and a renderer converts that text into vector graphics—usually SVG. Because the source is text, you can diff diagrams in Git, embed them beside code in Markdown, and regenerate visuals without dragging boxes in a GUI.

WebStatus.in bundles the Mermaid npm package and runs it in your browser: the diagram you see is produced locally from the text in the editor, with strict security settings appropriate for untrusted input.

How the WebStatus.in editor is laid out

This page embeds the same Mermaid tool as the standalone route /mermaid. You get a line-numbered source editor on one side and a live preview on the other. On small screens, Code and Preview appear as tabs so you can focus on writing or inspecting the diagram without squeezing both panes at once.

The preview does not re-render on every keystroke: it waits briefly after you stop typing, then parses and draws the diagram. That keeps the UI responsive when you paste large definitions or iterate quickly.

Step-by-step Mermaid tutorial

For flowcharts, sequence diagrams, state diagrams, syntax habits, and links to the official Mermaid documentation, use the free education article at https://webstatus.in/education/how-to-use-mermaid-diagram-editor (also opens from the Guide button in the toolbar).

The content below stays specific to this WebStatus.in implementation—preview behavior, toolbar actions, export, sharing, and data handling—so the tutorial and product reference stay easy to maintain separately.

Canonical syntax reference: https://mermaid.js.org/

Themes: default, dark, and forest

Open the More section in the toolbar to choose a theme. The selection is stored in this browser (local storage) with your diagram text so the next visit restores both. Themes change colors and contrast of the rendered SVG only; they do not alter your source.

Toolbar reference: everything this implementation offers

The sticky toolbar groups actions you will use in real docs and incident workflows. Here is how each feature behaves in this product—not generic Mermaid trivia.

Guide: opens /education/how-to-use-mermaid-diagram-editor (step-by-step Mermaid tutorial) while you keep editing on /mermaid or this page.
Save + info: opens local snapshots. Save snapshot stores the current source and theme under a name on this device; Load restores a snapshot into the editor. Data never leaves the browser for snapshots; clearing site data removes them.
Share: copies a link that encodes your diagram (and theme). Short links may use server-side storage when enabled; otherwise a long URL with a fragment can carry the payload. You may see a consent step before we create a short link.
More / Less: expands or collapses theme chips, templates, clipboard and file actions, and export buttons.
Sequence / State: one-click inserts canonical starter templates so you do not memorize boilerplate.
Copy / Paste: copies the raw Mermaid text or pastes from the system clipboard into the editor (subject to browser permissions).
Import: reads a local .mmd, .txt, or plain-text Markdown file into the editor—useful for diagrams saved next to repos.
SVG: downloads the last successfully rendered SVG from the preview. Fix parse errors first if the button stays disabled.
PNG: rasterizes that SVG inside your browser at 2x scale on a white background for slides or chat apps. Extremely large diagrams can exceed canvas limits; prefer SVG for infinite zoom.
Sample / Clear: Sample restores the built-in demo; Clear empties the editor and removes share state from the URL hash on this tab.

Size limits, performance, and errors

The editor caps source length to protect the browser from runaway pastes. The toolbar shows line count and approximate byte size so you know when you are approaching the limit.

Render failures display as plain text in the preview pane. Common causes include typos, wrong diagram keywords for this Mermaid version, or features gated by securityLevel strict (the configuration we use for safer rendering).

Desktop preview: sticky pane and toolbar height

On large screens the preview column can stick under the navigation while you scroll long source files. The layout subtracts the measured toolbar height so the preview does not jump under the sticky header. If you collapse the toolbar, the offset updates automatically.

Use cases that fit this workflow

Teams use text-first diagrams for README architecture blocks, RFC appendices, onboarding checklists, API sequence traces, and lightweight incident timelines. Export SVG when you need crisp docs; PNG when a stakeholder wants a quick thumbnail.

Privacy, sharing, and local data

Core rendering and SVG generation happen in your tab. Snapshots and autosaved text live in local storage until you clear them. Sharing is optional: only when you copy a share link (and confirm short-link flows when shown) can diagram data traverse the network under the policies described on-site.

Do not embed secrets, credentials, or personal data in diagrams you intend to share or screenshot; treat exported files like any other artifact you might commit or upload.

Frequently asked questions

Mermaid