Is it possible to comment out lines of diagram syntax?

+7 votes
asked Oct 25, 2013 in To be sorted by anonymous

Sometimes I want to comment out portions of the diagram syntax, similar to what I would do in source code, such as:

component a

component b

component c

component d


a -> b

b -> c


c -> d

d-> e



Is there someway todo this?  


Great product BTW!

2 Answers

+9 votes
answered Oct 25, 2013 by plantuml (295,000 points)

You can use quote like in the following example

' This is a comment on a single line
Bob->Alice : hello

/' You quote alors use slash-and-quote
to split your comments on several
lines '/


commented Apr 21, 2016 by anonymous
I'd be nice to have a link to documentation on this.
commented Apr 10, 2019 by anonymous
commented May 17, 2020 by obieeclark (100 points)
This is a very subtle clue in the documentation.   Could somebody add a more clear/less minimalistic sentence to this documentation?    We are trying to make Plantuml the standard for our company but minimalistic documentation is a real problem...
commented May 17, 2020 by plantuml (295,000 points)
Yes, you can indeed add a more clear sentence to the documentation. This is 100% open.

Just go to

PlantUML is a free, collaborative and open source project.

Thanks for your help !
commented Nov 9, 2020 by Jean
Is the documentation contents available on GitHub? I don't see it at

The official website is becoming unusable due to aggressive ads, and looks very unprofessional when I try to promote the project at work.
commented Nov 9, 2020 by plantuml (295,000 points)
PlantUML software is free but unfortunately we do have to earn something somehow. Note that we have just slightly decreased the level of ads.

Our patreons have access to an ads-free version of the documentation website. If you just send an email to we would be glad to offer you such an access so that you can see how it looks like.

commented Nov 9, 2020 by Jean
I understand that ads support the project, but at some point it starts to do more harm than good. Pardon me for pointing it out, but I doubt I'm alone in this impression.

Even if I got a an ad-free version, anyone I refer to the site will still get more than 50% of the screen taken up by ads on the first screen of any page.
+1 vote
answered Jul 2, 2020 by Krishnan

Line comments use a single apostrophe

' This is a comment

Block comments use C-style comments except that instead of * you use an apostrophe


many lines