# PlantUML

16 Hacker News commenters recommended PlantUML and 2 criticized it, November 2025 to November 2026. It was recommended in 6 of 13 months. It meets the Hacker Approved badge rule.

**Verdict:** Plain-text diagrams with strong control and tooling; the usual caveat is harder setup and no native GitHub rendering.

## Why people recommend it

- Fine control over output styling (3 comments): "has been the most customizable and flexible for me" ([source](https://news.ycombinator.com/item?id=49865850)) "much more expressive when it comes to styling" ([source](https://news.ycombinator.com/item?id=46814075)) "you have a lot more control over the output" ([source](https://news.ycombinator.com/item?id=47572695))
- C4 diagrams built into stdlib (3 comments): "see Structurizer or plant uml c4 for text portable examples" ([source](https://news.ycombinator.com/item?id=46797155)) "I'm a huge fan of both C4 and plantuml" ([source](https://news.ycombinator.com/item?id=49849880)) "Plantuml includes C4 in stdlib" ([source](https://news.ycombinator.com/item?id=49842269))
- Text diagrams better than images (2 comments): "A better way is to auto-generate e.g., class diagrams using PlantUML or Mermaid." ([source](https://news.ycombinator.com/item?id=46077033)) "diagrams as code like PlantUML or Mermaid are better than an image!" ([source](https://news.ycombinator.com/item?id=47168508))

## What people warn about

- Fiddly setup and tuning (2 comments): "every hour I spent fiddling with a Plantuml diagram to get the relation directions" ([source](https://news.ycombinator.com/item?id=49865601)) "Plantuml is much more annoying to setup, and doesn't render natively on GitHub" ([source](https://news.ycombinator.com/item?id=49875374))
- Line routing breaks with many lines (2 comments): "every hour I spent fiddling with a Plantuml diagram to get the relation directions" ([source](https://news.ycombinator.com/item?id=49865601)) "The routing tends to blow up when you have a bunch of lines" ([source](https://news.ycombinator.com/item?id=49601978))

## Alternatives hackers recommend

- [Mermaid](https://hackerapproved.com/p/mermaid.md): 93 recommend
- [Reladraw](https://hackerapproved.com/p/reladraw.md): 28 recommend
- [SQL to ER diagram tool](https://hackerapproved.com/p/free-sql-to-er-diagram-tool.md): 27 recommend
- [D2 diagram language](https://hackerapproved.com/p/d2.md): 21 recommend
- [Graphviz](https://hackerapproved.com/p/graphviz.md): 13 recommend

## Cite as

Hacker Approved, "PlantUML", https://hackerapproved.com/p/plantuml/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).