A detailed comparison of PlantUML and Mermaid to help you choose the right tool for your needs.
Open-source tool for creating UML diagrams from plain text
JavaScript-based diagramming tool that generates diagrams from text
| Plan | PlantUML | Mermaid |
|---|---|---|
| Free Tier | ✓ Completely free | ✓ Completely free |
| Lowest Paid | Free | Free |
| Enterprise | Free (self-hosted option) | Free |
| Feature | PlantUML | Mermaid |
|---|---|---|
| Text-to-diagram | ✓ | ✓ |
| UML diagrams | ✓ | — |
| Sequence diagrams | ✓ | ✓ |
| Class diagrams | ✓ | ✓ |
| Use case diagrams | ✓ | — |
| Activity diagrams | ✓ | — |
| Component diagrams | ✓ | — |
| Open source | ✓ | — |
| Self-hostable | ✓ | — |
| IDE integrations | ✓ | — |
| Flowcharts | — | ✓ |
| Gantt charts | — | ✓ |
| GitHub integration | — | ✓ |
| Markdown compatible | — | ✓ |
| JavaScript library | — | ✓ |
| Live editor | — | ✓ |
| Themes | — | ✓ |
| Open Source | ✓ | ✓ |
| Rating | ⭐ 4.5 | ⭐ 4.4 |
Choose PlantUML if: You need developers who prefer text-based diagramming and need uml diagrams. PlantUML excels with its completely free and text-based (version control friendly).
Choose Mermaid if: You need developers and technical writers needing text-based diagrams for documentation. Mermaid stands out with its completely free and text-based (version control friendly).
Best free option: Both PlantUML and Mermaid offer free tiers. PlantUML offers "Completely free" while Mermaid offers "Completely free".
It depends on your needs. PlantUML is better for developers who prefer text-based diagramming and need uml diagrams, while Mermaid is better for developers and technical writers needing text-based diagrams for documentation. Both are excellent tools rated 4.5 and 4.4 respectively.
PlantUML starts at Free while Mermaid starts at Free. Both offer free tiers.
Most tools offer import/export features to help you migrate. We recommend trying Mermaid's free tier before fully committing to a switch.
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