Confluence doesn't support Mermaid natively — the code block macro will syntax-highlight your Mermaid, but it won't render it. You need a marketplace app, and there are more than a dozen. Here's an honest comparison of the options that matter, including where each one falls short.
| App | Price | Best for | Watch out for |
|---|---|---|---|
| Mermaid Diagrams Pro (this site) | Free ≤10 users, then $0.35/u/mo | Teams that want dark mode, zoom & migration | New app (2026) — smaller review history |
| Mermaid diagrams viewer (Atlassian Labs) | Free | Casual/occasional use | 2.9★ — slow rendering, auto-detect misses, no support |
| Mermaid Chart for Confluence (official) | Free install, paid Mermaid SaaS | Teams already on Mermaid Chart cloud | 3.0★ — small renders, no zoom, white-box dark mode |
| Mermaid Diagrams for Confluence (Stratus) | $0.40/u/mo | — | Frozen since Sept 2025; unfixed critical bugs in reviews |
| PlantUML+Mermaid multi-format apps | ~$0.25/u/mo | Mixed-format teams | Jack-of-all-trades UX |
| draw.io | ~$1.95/u/mo | Visual (drag-drop) diagramming | Mermaid is an import, not a first-class citizen |
Some apps store your source on the vendor's servers; some in page attachments; the best store it in the page itself. If the vendor disappears (it happens — the Connect-era app freeze of 2025-2026 orphaned several), you want your source in your pages. Mermaid Diagrams Pro stores source as macro data inside the page: it's in your exports, your page history, your copies.
The single most common complaint in this category's reviews: white diagram boxes on dark pages. Test it: switch your Confluence theme and watch whether the diagram re-renders. (Ours does, instantly, without a refresh.)
Zoom and fullscreen sound trivial until you publish a 40-node flowchart. The official Mermaid Chart app's most-repeated review complaint is diagrams rendering tiny with no way to zoom.
Check the listing's version history. The legacy Stratus app — long the category leader — hasn't shipped a release since September 2025, and its recent reviews report critical errors with no vendor response. Mermaid evolves fast; a frozen app falls behind the language itself.
Apps with the Runs on Atlassian badge render entirely inside Atlassian's infrastructure — no external servers see your diagram code. If your security team reviews vendors, this badge shortens that conversation considerably.
Atlassian Labs viewer — free and fine for an occasional diagram in a code block. It's an unsupported Labs experiment: rendering is slow on big pages, auto-detection misses code blocks, and there's nobody to email when it breaks.
Mermaid Chart (official) — made by the company behind mermaid.js, and best if your team already lives in their SaaS editor. As a Confluence experience it disappoints: reviews consistently cite small fixed-size renders, missing zoom, and broken dark mode.
Stratus Mermaid Diagrams — was the category standard for years and stores source in attachments (good!). But it's been frozen for a year, sits on the deprecated Connect platform, and unresolved bugs are piling up in reviews. If you're on it, plan your exit — see our migration guide.
Mermaid Diagrams Pro — we built it around this list: source in the page, instant dark-mode, zoom/fullscreen and SVG/PNG export on every diagram, live-preview editor, friendly errors, Runs on Atlassian, and a one-click importer from the Stratus app. We're the newest entrant, which means fewer reviews than incumbents — and it means your feature requests actually get built.
Try any of these free — most offer trials or free tiers. If you're comparing for a team, test the three questions above: dark mode, zoom, and where your code lives.