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Browser editor for Mermaid diagrams with live preview, an AI helper and image export
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.
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 ↗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.
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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