Guide · Confluence Cloud
Diagrams as code in Confluence Cloud: Mermaid or PlantUML
“Diagrams as code” means you type a diagram as text and a tool draws it. The text lives in the page, so anyone can change one line instead of redrawing boxes, and you can copy the same text into Git, a README or a pull request. Confluence Cloud does not draw diagram code on its own, so you need an app. This guide shows which language fits which diagram, which apps draw them, and what to check before you choose.
Disclosure: Dortus makes diagram editors for Confluence Cloud, including one of the apps below. Corrections are welcome at support@dortus.com.
Mermaid or PlantUML: which one for which diagram
The two languages overlap, but each is stronger at different things.
| Diagram | Mermaid | PlantUML |
|---|---|---|
| Flowchart | Yes, short syntax | Yes (activity diagram) |
| Sequence diagram | Yes | Yes, with more layout options |
| Class diagram | Yes | Yes |
| Component, deployment, use case | Partly: C4 and architecture diagrams, still marked experimental in the Mermaid docs | Yes |
| Gantt chart, timeline | Yes | Gantt yes |
| Mind map | Yes | Yes |
| Entity relationship (database) | Yes | Yes (IE and Chen notation) |
| Where else it works | GitHub, GitLab, Azure DevOps and many Markdown tools draw it | Many IDE plugins and documentation tools; GitHub shows it only as code |
Wide table: scroll sideways on a small screen. Based on the Mermaid and PlantUML documentation.
Rule of thumb. Start with Mermaid if your team writes flowcharts, sequence diagrams and plans, and already uses Markdown in Git. Pick PlantUML if you need the full UML set, or if you already have .puml files from an older wiki or Confluence Server. Many teams end up with both: Mermaid for quick sketches, PlantUML for architecture.
The same diagram in both languages
A login flow as a sequence diagram. Mermaid:
sequenceDiagram
User->>App: Log in
App->>Auth: Check password
Auth-->>App: OK
App-->>User: WelcomePlantUML:
@startuml
User -> App : Log in
App -> Auth : Check password
Auth --> App : OK
App --> User : Welcome
@endumlFor a diagram like this the two are almost the same. The difference shows up in bigger diagrams: PlantUML has more control over layout and more UML types, Mermaid is shorter and draws in more places outside Confluence.
Apps that draw diagram code in Confluence Cloud
From the Atlassian Marketplace listings for Confluence Cloud on 2 November 2026. “RoA” is the Runs on Atlassian badge: the app runs on Atlassian's own platform and sends no data to servers outside Atlassian. Installs change every day; the listing shows the current number.
| App (vendor) | Languages | Price | RoA badge |
|---|---|---|---|
| Mermaid diagrams viewer (Atlassian Labs) | Mermaid | Free | Yes |
| Mermaid Diagrams for Confluence (Stratus Add-ons) | Mermaid | Paid | No |
| Mermaid (Narva Software) | Mermaid | Free | Yes |
| Mermaid Editor for Confluence (Dortus) | Mermaid | Free | Yes |
| PlantUML Diagrams (Stratus Add-ons) | PlantUML | Paid | No |
| PlantUML (Instant Diagrams) (AppsFoundry) | PlantUML | Free | No |
| Flowchart & PlantUML (Toshihiro Sato) | PlantUML, flowchart | Paid | No |
| PlantUML for Confluence Cloud (Narva Software) | PlantUML | Free | Yes |
| Excalidraw, Mermaid, PlantUML (Fulstech) | Mermaid, PlantUML, Excalidraw | Paid | No |
| Mermaid Diagrams & Charts and PlantUML Diagrams & Charts (RVS Softek) | Mermaid, PlantUML (two apps) | Free | No |
Wide table: scroll sideways on a small screen. Twelve Mermaid apps in more detail: Mermaid apps for Confluence Cloud compared. Dortus also has a PlantUML editor; on 4 November 2026 it was still waiting for Marketplace approval, so it is not in this table.
What to check before you pick an app
- Does the data have to stay in Atlassian? Some PlantUML apps send the code to a PlantUML server to draw it. Look for the Runs on Atlassian badge, or read the listing's privacy and security section.
- Can people edit the diagram on the page? An editor with code and a live preview side by side is easier for people who do not write diagram code every day.
- Do you export pages to PDF or Word? Not every app puts the drawn diagram into an export. Test one with your own diagram.
- Dark mode. Some apps follow Confluence's dark theme; others draw a white diagram on a dark page.
- Price per user. Marketplace prices count every user on the site, not only the people who draw.
- Coming from Confluence Server or Data Center? Old diagram macros often stop working after a move to Cloud: the page shows “Unknown macro” or “Error loading the extension!” where the diagram was. The diagram code is usually still in the page, so it can be moved into a Cloud app. Check this before the move, not after.
FAQ
Can Confluence Cloud draw diagrams from code without an app?
No. In our tests in October and November 2026, Mermaid or PlantUML code pasted into a Confluence Cloud page stayed a code block. You need an app from the Atlassian Marketplace, or you draw the diagram elsewhere and upload a picture, which you then cannot edit on the page.
Should I use Mermaid or PlantUML in Confluence?
Use Mermaid for flowcharts, sequence diagrams, Gantt charts, mind maps and timelines when you want short, readable code that many developers already know from GitHub and GitLab. Use PlantUML when you need the full set of UML diagrams, such as class, component, deployment, use case and activity diagrams, or when your team already has PlantUML files. Many teams use both.
Is there one app for both Mermaid and PlantUML in Confluence Cloud?
Yes. On 2 November 2026 Fulstech's Excalidraw, Mermaid, PlantUML app listed both, as did RVS Softek with separate free apps for Mermaid and for PlantUML. Most other apps do one language. Check the listing for the Runs on Atlassian badge and PDF export before you choose.
Which diagrams-as-code apps for Confluence keep data inside Atlassian?
Look for the Runs on Atlassian badge on the Marketplace listing. On 2 November 2026 it was shown, among others, by Mermaid diagrams viewer (Atlassian Labs), Mermaid and PlantUML for Confluence Cloud (Narva Software) and Mermaid Editor for Confluence (Dortus). The most installed PlantUML app, PlantUML Diagrams by Stratus Add-ons, did not show the badge.
How we checked
On 2 November 2026 we read the public Atlassian Marketplace listings for Confluence Cloud, without logging in and without installing the other apps. We wrote down only what the listing said, so this page says nothing about how well each app works. For our own app the facts come from its code and changelog. If something is wrong or out of date, email support@dortus.com and we will correct it.
More
Mermaid Editor for Confluence by Dortus
Type the diagram, watch it draw
Mermaid code on the left, a live preview on the right that redraws as you type. Free, Runs on Atlassian, no outside account.
Get it free on the Atlassian Marketplace
Not a Confluence admin? In Confluence, open Apps, then Explore apps, search for Mermaid Editor for Confluence and send a request. Your admin gets an email and can install it.
See also: How to add Mermaid diagrams to Confluence Cloud, Mermaid examples to copy and Sequence diagrams in Confluence Cloud.