Paste any PlantUML source — activity, sequence, swimlane, class, or state — and the beautifier rewrites the render with a theme-matched palette, cleaner spacing, and orthogonal edges suited for product docs, slide decks, and runbooks. Free, online, no signup. Export as SVG or HD PNG when ready.
An activity flow, a coloured swimlane runbook, and a three-actor sequence diagram — all PlantUML, all rendered by the same beautifier. Click Open in editor on any sample to load the source and watch the layout transform.
Activity grammar with `if-else` and named lanes. Beautified output gives each lane a column, routes the rejection branch as an L-shape, and applies a theme-matched palette.
@startuml
|Employee|
start
:Submit reimbursement;
|Manager|
:Review request;
if (Approved?) then (yes)
|Finance|
:Process payment;
:Notify employee;
else (no)
|Employee|
:Receive rejection;
endif
stop
@endumlColored swimlanes with on-call escalation. Beautifier preserves your `|#Color|Name|` hints but maps them to a theme-coherent palette so the lanes stay readable on light and dark backgrounds alike.
@startuml
|#FFB6C1|Monitoring|
start
:Alert fires;
|#FFE4B5|On-call|
:Acknowledge alert;
:Initial diagnosis;
if (Known issue?) then (yes)
:Run runbook fix;
else (no)
|#B0E0E6|SRE Lead|
:Escalate & assist;
:Apply fix;
endif
|On-call|
:Write postmortem;
stop
@endumlThree-actor sequence with sync calls and async responses. Beautified render widens the actor lanes, separates request and return arrows visually, and uses theme-matched lifelines instead of PlantUML's default thin grey lines.
@startuml
participant Client
participant API
participant Auth
Client -> API: GET /profile
API -> Auth: validate(token)
Auth --> API: 200 OK + user
API --> Client: 200 OK + profile
@endumlPlantUML's reference renderer is excellent at correctness but produces output that looks dated next to modern product docs and slide decks. The beautifier is the polish step that turns the same source into something you would actually paste into work output.
Activity, sequence, swimlane, class, and state PlantUML sources all run through the same beautifier — one theme pick, one export pipeline, no per-type tooling.
The PlantUML beautifier rewrites the rendered layout, not your `@startuml` source. Copy the same source into any PlantUML server and it parses identically.
Replace PlantUML's 2005-era named colors with one of six palettes — Atlas / Modern for light docs, Obsidian / Slate for dark, Brutalist / Memphis for slides, Atelier for editorial.
Crisp SVG with fonts inlined for RFCs and Confluence. HD PNG sized for slide decks and tickets. Same beautified output, multiple destinations — no signup.
Strong support: activity diagrams (including swimlanes with `|lane|` syntax), sequence diagrams, and the activity-beta grammar (start, action, branch, switch, repeat-while). Partial: class, state, and component diagrams render with the same theme system but use a more general layout pass — bespoke beautification is on the roadmap. Use diagram-types/plantuml-* reference pages to see what currently renders cleanest.
This page is the umbrella for all PlantUML diagram types. /plantuml-activity-beautifier goes deeper specifically on activity grammar — swimlane lane layout, cross-lane edges, branch and repeat-while routing — with samples that exercise those features in detail. If you know your diagram is an activity flow, the activity page is the better starting point.
Yes. Anonymous use covers unlimited preview, beautify, and SVG / PNG export with a small watermark. Free accounts remove the watermark and persist diagrams to a personal hub. There is no per-diagram-type paywall — the same beautifier handles every supported type at the same plan tier.
The `@startuml` / `@enduml` block is preserved in the source you save. `skinparam` and `!theme` directives are read but the visual styling on export follows the Beauty Diagram theme you pick before exporting — that keeps the exported SVG self-contained and consistent across renderers, regardless of which PlantUML server processes the source elsewhere.
Yes. Crisp SVG with fonts inlined for product docs, RFCs, and Confluence pages — best when the diagram needs to scale or live inside a browser. HD PNG sized for slide decks, ticket attachments, and email-friendly destinations where SVG is not supported. Both formats keep the beautified layout — no manual repositioning after export.
Open the editor, paste your `@startuml` block, click beautify, export SVG or HD PNG. No signup.