Dashboard to monitor open source UML tools

UML is not dead. It has some issues, true. But as Bran Selic puts it, UML is the worst modeling language except for all the others. So it’s important to keep an eye on the best UML tools. And of course, I’m specially interested in open-source UML tools.

I was wondering how many open source UML tools are out there (and how maintained they are). Therefore, after the success of my dashboard of low-code tools, I decided to create a dashboard to monitor open source tools:

• The live UML dashboard  
• The GH repo hosting it (a ⭐ is appreciated)

Let’s discuss more about the tool selection process and some surprising findings

UML tools selection process

The selection method is based on the following inclusion criteria:

• Repositories that declare themselves as UML projects
• Repositories with more than 50 stars
• Active repositories (last commit is no more than 1 year ago)
• Tool aims to render, edit or generate from UML models

and exclusion criteria:

• Repositories with no information in English
• Repositories that were just created to host the source code of a published article
• Repositories that are awesome lists or collection of resources or examples

The final list is the intersection of the above criteria.

How many UML tools are out there?

Right now, we have 68 tools that comply with the above criteria. Not bad. Sure, there are many more open source low-code tools (which are also far more popular, in terms of number of stars) but considering that, for many, UML is dead, I’d say this shows that this is not really the case. Keep in mind that one of the selection criteria is that the tool is still somehow under development so we don’t count abandoned tools.  And in any case, we already discussed that many low-code tools come with DSLs that are just plain UML but with a coat of paint.

And while many of the tools were started a long time ago (during more the “golden years” of UML), we still see new UML tools popping up.

But how many UML tools, not relying on PlantUml, are really out there?

At the same time, we need to acknowledge the huge impact of PlantUML to create a viable ecosystem of UML tools. If we look closely at the list of open source UML tools, we can see that many are somehow derived from PlantUML, extending it in a number of ways. This shows the importance of textual UML tools and their impact in integrating UML modeling in software development pipelines.

How many UML tools target the low-code / no-code market?

Almost none. To me this is surprising as there is a lot of UML in low-code. And this should be even more the case with no-code tools

If it’s 0% code then it should be 100% modeling

But it’s not the case. There is no UML tool that tries to sell itself as no-code. Could it be that UML is perceived as too complex for non-technical users?

And only three, including, of course, our own BESSER tool, now with a graphical modeling editor, mention low-code in their description or tags.

Has AI been integrated in UML tools?

Not yet. In the research world, there is a growing number of approaches aimed at making modeling smarter by relying on Large Language Models or other AI techniques (e.g. see our tree-of-thoughts based approach) but these initiatives still need to make it into current UML tools.

Needless to say, I expect this to change in the near future. On our side, we are currently working on the integration of a chatbot in the modeling editor to advance in our low-modeling strategy.

Check out the dashboard

Check out the dashboard, play with it and let me know what you think. Here or in the dashboard GitHub repository.