MernyxFree to look and edit source. One purchase to draw with the mouse and deliver. Everything runs on your Mac — so the pricing is shaped like a tool, not a service.
During 0.x every capability is free. The paid tier switches on at 1.0 — the app enforces this itself, keyed to its version number.
$0forever
A complete product, not a demo.
$19one-time
Buy once. Updates never expire.
Students, educators and active open-source projects: free or 50% off —write to us.
The free tier is a complete viewer and source editor. The paid tier unlocks the mouse-driven canvas and delivery-grade export — the parts nothing else on macOS does.
| Capability | Free | Pro |
|---|---|---|
| View and render all 34 families | ||
| Edit Mermaid source with highlighting and diagnostics | ||
| Quick Look preview and Finder thumbnails | ||
| Export PNG / SVG / PDF without watermark | ||
| Export at 1× scale | ||
| Export at 2× / 3×, margins, batch export, presets | ||
| Structural canvas editing (add, connect, reconnect nodes) | ||
| Style editing (fill, stroke, text colour, width, opacity) | ||
| Label editing in 30 of 34 families | ||
| AI generate and fix — BYOK, never billed per use |
Mermaid Chart bills per person per month for cloud collaboration and SSO. OmniGraffle prices like a general canvas tool. Mernyx is a syntax tool that runs offline — so it prices like one.
Mermaid Chart
Free · Plus $10/mo · Premium $20/mo per user
Cloud collaboration, AI credits, SSO
OmniGraffle
$149.99 one-time, or $129.99/yr
General-purpose vector drawing
draw.io / diagrams.net
Free
Free online diagramming
mermaid.live
Free
In-browser rendering and export
Prices read from the vendors' public pricing pages, 2026-10. They change; check before comparing.
Yes — every capability is free while Mernyx is in 0.x. The paid tier described here switches on at version 1.0, and the app itself enforces that: the licensing gate is keyed to the version number, not to a server.
Everything — compiling, layout, export — runs locally, so there is no server cost to cover per user. A subscription would be paying for a service that does not exist. The one purchase is what funds keeping up with upstream Mermaid syntax, and it is the only purchase you make.
No. Updates are free for the life of the app — new diagram families, syntax support and rendering fixes all arrive through the regular update channel. There is no renewal date and no version that quietly stops working.
It is not. Mernyx uses bring-your-own-key: you configure your own AI endpoint and the key stays in your macOS keychain. Requests go from your machine to your provider — Mernyx never sees them, so there is nothing to bill.
Yes — free or 50% off for students, educators and active open-source projects. Write to us with a short description of what you are doing.
Today's build is entirely free. Download it, and see whether the canvas earns its price when 1.0 ships.
