Common Questions about yUML

What is yUML?

yUML is an online tool for creating and publishing simple UML diagrams. It's makes it really easy for you to:

  • Embed UML diagrams in blogs, emails and wikis.
  • Post UML diagrams in forums and blog comments.
  • Use directly within your web based bug tracking tool.
  • Copy and paste UML diagrams into MS Word documents and Powerpoint presentations.

Is it FREE?

Yup! This site is a free service - enjoy!

Can I buy a private copy?

Universities, businesses and some analysts may want their own private installation of yUML on their own computers. We sell the source code and support on our business license page.

Why should I use yUML?

yUML saves you time. It's designed to for those that like to create small UML diagrams and sketches.

Without yUML, creating a UML diagram might involve loading up a UML tool, creating a diagram, giving it a name, fiddling with layout, exporting it to bitmap, and then uploading it online somewhere. yUML doesn't make you do any of that.

Why should I NOT use yUML?

yUML is designed for light, back-of-napkin style UML usage. This won't suite every project. Desktop tools tend to offer more control over layout, more diagram types, fuller support for the UML specification etc. If you want all that stuff, we suggest taking a look at UMLet - a nifty free desktop tool.

What types of yUML diagram are supported

Right now class and use case diagrams are supported. Activity and State diagrams will come along shortly.

A yUML use case diagram looks like this:

UML use case diagram

And a class diagram looks like this:

UML class diagram

You might not be a "scruffy lover", so you can do plain ones too:

UML class diagram

There's loads more you can do like adding colour, notes, scaling etc. To learn about that, see the samples or try creating a diagram yourself!

How do I use characters in yUML like # , and ( ?

yUML won't allow certain characters in the diagram definition. So you have to find a unicode character that looks like the standard ASCII one.

You can find those at

For example, if you want to use a hash #, then you can see alternative characters on this search result. In this case, the full width number sign ( #) looks like a regular hash, and can be used in yUML.

What is UML?

It's a particular way of drawing diagrams. It stands for Unified Modelling Langage.

UML is often used by business analysts and software developers. Schools often teach it as part of IT and software courses. If you read a lot of software text books or articles, you'll probably have seen quite a lot of UML

Wikipedia gives a fairly good description of UML. The Object Management Group also talk about it a little ;)

Is't UML evil?

UML is evil when you use it too much for your given project; it's easy to burn hours and hours doing UML stuff when you could be writing code or doing something more useful. Some projects use a lot of UML and that really helps them.

Here at Pocketworks we use UML sparingly; like scribbling it on napkins and whiteboards, or putting small fragments of UML in our documentation to help get a point across. That's why we created yUML - it's perfect for that mindset :)