Comparison

Lucid Train compared with PlantUML.

PlantUML has been the diagram-as-code default for years, and both of its main limitations are the same age.

Download for macOS

v0.1.33 · .dmg · Apple Silicon & Intel

Signed & notarized by Apple · opens without a Gatekeeper warning

sha256 698955a0187bc039f4c74f5d05a9f10fbb27376a45788a0a241d1326b73873c7

Download for Windows instead

$curl -fsSL https://lucidtrain.com/install.sh | sh

What PlantUML is better at

Coverage and scriptability. It draws every UML diagram type plus a great deal more, it is free, it runs anywhere Java runs, and it integrates with essentially every documentation toolchain in existence. For generating diagrams in a build pipeline from text held in version control, it is proven and unglamorous in the best way.

Where Lucid Train is different

You write PlantUML by hand; Lucid Train reads your repository. And PlantUML's default layout comes from Graphviz, which is capable but produces the characteristic dense, slightly awkward output that people either accept or fight with layout hints. ELK is a newer layered solver that handles orthogonal routing and grouping better, which shows most on larger diagrams.

Aesthetics matter more than they should

PlantUML's default styling is dated, and while it is themeable, most teams do not theme it. A diagram people find unpleasant to look at is a diagram that does not get put in front of people, which is a real cost even though it is not a functional one.

Text as the source of truth

If your requirement is that diagrams live as text in the repository and render in CI, PlantUML does that well and this does not replace it. Ask the agent for PlantUML and it writes it, which is often the pragmatic combination: generated content, in the format your toolchain already builds.

Side by side

	Lucid Train	PlantUML
Price	CLI free; desktop $3/month	Free, open source
Authoring	Generated from code or prompt	Written by hand
Layout engine	ELK	Graphviz, usually
Diagram types	Architecture focused	Very broad, all of UML
Renders in CI	No	Yes, standard practice
Real service icons	Yes, bundled	Sprite libraries
Diagram to code	Yes	No
Runs offline	Yes	Yes

FAQ

Questions

Can Lucid Train output PlantUML?

Yes, on request. The canvas exports as SVG, PNG or an Excalidraw scene.

Is PlantUML's layout really worse?

On small diagrams there is little in it. On larger ones Graphviz's approach produces more crossings and less predictable grouping than a layered solver, and the workaround is manual hints, which is the thing diagram-as-code was meant to avoid.

Which for UML specifically?

PlantUML, if you need the full range of UML types and specification-shaped output. This draws the four types teams actually use and does not attempt the rest.

Affiliation

Lucid Train is an independent product and is not affiliated with, endorsed by, or connected to the product described on this page. All names and trademarks belong to their respective owners. Pricing and features were checked on 19 August 2026 and change without notice; check the vendor's own site before deciding.

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Lucid Train vs Mermaid
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