Mermaid Viewer
Verified Oct 16, 2026 ActiveBrowser editor for Mermaid diagrams with live preview, an AI helper and image export
Listed on EffectHub ·
Pricing
- Pricing model
- Freemium
- Paid options from
- $69.99/yr
- Billing
- Yearly
Starter is $69.99/year (30 diagrams, 500 AI conversations a month, high-resolution PNG); Pro is $119.99/year (unlimited diagrams and conversations, all export formats, priority support). There is no monthly option. The free tier allows 3 diagrams, 5 AI conversations a day and watermarked low-resolution PNG.
Use tool ↗About Mermaid Viewer
Mermaid Viewer is an online editor for Mermaid, the text syntax that renders flowcharts, sequence diagrams and the rest as code. You type or paste Mermaid on one side, watch the chart redraw on the other, then export it or share a link — no local toolchain to install. A GPT-4-backed assistant will write or repair the Mermaid source from a plain description, and that is the part the plans meter. The free tier stops at 3 saved diagrams, 5 AI conversations a day and a watermarked low-resolution PNG. Paid tiers are yearly only: $69.99 a year for 30 diagrams and 500 AI conversations a month, $119.99 a year for unlimited diagrams and every export format. The site names no company, only a support address and a 2024 copyright line.
- Platforms
- Web · VS Code extension
- API
- Not confirmed
- Last verified
- Oct 16, 2026
Verified sources
- Browser-based Mermaid editor with live preview, GPT-4 assistance and export; free/Starter/Pro tiers at $0, $69.99/yr and $119.99/yrmermaidviewer.com ↗
- Legal pages carry only a support email and a 2024 MermaidViewer copyright line, with no company entity namedmermaidviewer.com ↗
Is Mermaid Viewer legit?
We don’t label tools safe or unsafe. Below are the records we checked ourselves, each with the date we read it.
- Domain registered
- Feb 11, 2025 (1 year ago)Registry record (RDAP), registrar Spaceship, Inc., looked up Sep 6, 2026
- TLS certificate
- Issued by Google Trust Services, valid until Dec 25, 2026Seen in our own connection to the site on Oct 16, 2026
- Last checked
- Oct 16, 2026The site answered
Pros & cons of Mermaid Viewer
If you already write Mermaid, this is a fast place to iterate on it without setting up a renderer, and the AI helper is genuinely useful for the syntax you can never remember. The value proposition thins out once you notice the Mermaid Live Editor does the core job for nothing, so you are really paying for saved diagrams, unwatermarked export and the AI.
Pros
- Live preview updates as you type, with shareable diagram links
- AI assistant drafts and fixes Mermaid source from a description
- Exports to several formats, including high-resolution PNG on paid tiers
- A VS Code plugin is offered alongside the web editor
Cons
- Paid plans are annual only — there is no month-to-month escape hatch
- Free output is watermarked and capped at 3 saved diagrams
- No company, country or team is disclosed anywhere on the site
Best for
- Developers and technical writers who already keep diagrams as Mermaid source
- Anyone who wants Mermaid rendering without installing a local toolchain
- Quickly repairing Mermaid syntax errors with a prompt instead of docs
Not for
- Freehand or drag-and-drop diagramming — everything here starts as code
- Teams needing real-time multi-user collaboration on a shared canvas
Watch out: The official Mermaid Live Editor renders and exports the same diagrams free of charge, so weigh the annual fee against what the AI helper and saved-diagram limits are actually worth to you.
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