Mermaid vs PlantUML vs Graphviz for Confluence: Which Diagram Tool to Choose
Mermaid, PlantUML, and Graphviz are the three most popular text-based diagramming languages. Mermaid is the easiest to learn and covers the widest range (29 diagram types). PlantUML excels at detailed UML with precise notation control. Graphviz is best for technical network and dependency graphs. Most Confluence teams should start with Mermaid and add Graphviz for network diagrams if needed.
- The strengths and weaknesses of each tool
- Which diagram types each one supports
- How easy each is to learn and use
- A practical recommendation for Confluence teams
Text-based diagramming — writing a few lines of code that render into a diagram — is how modern teams keep diagrams in sync with their documentation. No more drawing boxes by hand in Visio, exporting screenshots, and pasting them into Confluence where they go stale. With text-based diagrams, you edit the source and the diagram redraws instantly.
But there are three major text-based diagramming languages, and they are not interchangeable. Each has different strengths, different syntax, and different ideal use cases. This guide compares Mermaid, PlantUML, and Graphviz so you can choose the right one (or combination) for your Confluence team.
Mermaid: the all-rounder
Mermaid is the most popular text-based diagramming language, and for good reason. It is easy to learn, supports the widest range of diagram types, and has the best ecosystem of Confluence integrations.
Strengths:
- 29 diagram types — flowcharts, sequence, class, state, ER, Gantt, pie, C4, mindmaps, user journeys, and more
- Simple syntax — a flowchart is literally
A --> B --> C - One-click templates — every diagram type ships with a working starting point
- Live preview — see the diagram render as you type
- Themes and dark mode — customize colors, fonts, and auto-adapt to dark mode
- Best Confluence support — dedicated macros with deep integration
Weaknesses:
- Less precise control over layout than Graphviz for complex graphs
- UML notation is not as detailed as PlantUML for strict UML compliance
- Very complex diagrams can become hard to read in the source
Best for: Teams that need a wide variety of diagram types (flowcharts, Gantt charts, ER models, sequence diagrams) with an easy learning curve. This covers 90% of what most Confluence teams need.
Example syntax (flowchart):
graph TD
A[User Request] --> B{Authenticated?}
B -->|Yes| C[Process Request]
B -->|No| D[Redirect to Login]
C --> E[Return Response]
PlantUML: the UML specialist
PlantUML is the go-to for teams that need strict, detailed UML diagrams — particularly class diagrams, component diagrams, and sequence diagrams with precise notation.
Strengths:
- Deepest UML support — class, object, component, deployment, activity, state, and sequence diagrams with full UML 2.x notation
- Precise control — detailed styling, skin parameters, and layout hints
- Rich syntax — supports notes, grouping, partitions, and complex relationships
- Available in Markdown macros — Enhanced Markdown for Confluence renders PlantUML inline
Weaknesses:
- Steeper learning curve — the syntax is more verbose and less intuitive than Mermaid
- Narrower scope — focused on UML; less suited for flowcharts, Gantt charts, or mindmaps
- Fewer Confluence integrations — typically rendered through a Markdown macro or a dedicated PlantUML server, not a standalone Confluence macro
- Server dependency — traditional PlantUML requires a rendering server (though some macros handle this)
Best for: Engineering teams that produce formal UML documentation — architecture specs, detailed class hierarchies, and component interaction diagrams — where UML compliance matters.
Example syntax (sequence diagram):
@startuml
actor User
participant "Order Service" as OS
participant "Payment Gateway" as PG
User -> OS: Place order
OS -> PG: Charge payment
PG --> OS: Payment confirmed
OS --> User: Order confirmed
@enduml
Graphviz: the graph engine
Graphviz (DOT language) is a layout engine for graphs where the structure matters more than the visual styling. It is unmatched for technical network diagrams, dependency graphs, and organizational charts with many nodes.
Strengths:
- Superior automatic layout — the Graphviz layout engine handles complex graphs with hundreds of nodes and produces clean, readable layouts
- Technical and precise — ideal for dependency maps, call graphs, state machines, and network topologies
- DOT syntax — compact and focused on nodes and edges
- Dedicated Confluence app — Graphviz Charts for Confluence with live preview
Weaknesses:
- Aesthetic style — diagrams look technical and utilitarian, not polished or hand-drawn
- Limited diagram types — primarily directed and undirected graphs; no native Gantt, pie, or mindmap support
- Less intuitive — DOT syntax is straightforward but the layout engine's behavior can be unpredictable for custom positioning
Best for: DevOps and infrastructure teams documenting network topologies, service dependencies, and system call graphs. Also strong for large organizational charts that auto-layout engines handle well.
Example syntax (dependency graph):
digraph dependencies {
API -> AuthService
API -> Database
AuthService -> Redis
Database -> BackupService
API -> MessageQueue
MessageQueue -> Worker
}
Side-by-side comparison
| Feature | Mermaid | PlantUML | Graphviz |
|---|---|---|---|
| Diagram types | 29 (widest) | ~12 (UML-focused) | 2 (directed/undirected graphs) |
| Learning curve | Easy | Moderate | Easy |
| Best at | Flowcharts, Gantt, ER, mindmaps | Class, sequence, component UML | Network graphs, dependency maps |
| Layout control | Moderate | Moderate | Strong (automatic) |
| Visual style | Clean, modern, themeable | Formal UML | Technical, utilitarian |
| Dark mode | Yes (auto) | Via skin params | Via color schemes |
| Confluence integration | Dedicated macro (Mermaid Plus) | Via Markdown macro | Dedicated macro (Graphviz Charts) |
| Template library | 29 one-click templates | Community examples | Limited |
| Free for ≤10 users | Yes | Yes (via Enhanced Markdown) | Yes |
Recommendation for Confluence teams
Start with Mermaid. It covers the widest range of diagram types, has the easiest learning curve, and has the best Confluence integration (Mermaid Plus for Confluence with 29 one-click templates). For most teams, Mermaid alone handles 90% of diagramming needs.
Add Graphviz if you do network/infrastructure diagrams. DevOps and infrastructure teams benefit from Graphviz's superior auto-layout for complex dependency graphs and network topologies. Graphviz Charts for Confluence is a separate, complementary app.
Use PlantUML if you need strict UML. If your architecture documentation requires formal UML 2.x notation — detailed class hierarchies, precise component diagrams — PlantUML (available via Enhanced Markdown for Confluence) is the right tool. For most teams, Mermaid's UML support is sufficient.
The practical combination many teams land on: Mermaid Plus for Confluence for flowcharts, ER, Gantt, and sequence diagrams + Graphviz Charts for Confluence for network and dependency graphs. This duo covers virtually every diagramming need in a typical engineering organization.
Explore diagram solutions
Browse our diagram solutions to see how Mermaid, Excalidraw, and Graphviz fit together for Confluence teams, or compare the apps side by side in the full catalog.
Frequently Asked Questions
Can I convert between Mermaid and PlantUML?
Not directly. The syntaxes are different enough that there is no reliable automatic converter. If you switch tools, you rewrite the diagrams. This is why it is worth choosing the right tool upfront.
Which tool has the best Confluence integration?
Mermaid has the deepest Confluence integration through Mermaid Plus for Confluence — a dedicated macro with live preview, 29 templates, themes, and dark mode. Graphviz Charts for Confluence offers a similar dedicated experience for DOT diagrams. PlantUML is typically rendered through a Markdown macro rather than a standalone diagramming macro.
Do I need a separate server for any of these?
No. All three can render entirely client-side or via Atlassian Forge compute — no external rendering server required. Avoid older PlantUML integrations that depend on a self-hosted PlantUML server.
Explore diagram solutions or browse the full app catalog to compare Mermaid, Graphviz, and Excalidraw for Confluence.
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