Ask HN: Is UML still relevant today?

Yes,it helps communicate ideas between engineers and is not bound to any paradigm. UML can even be a great tool to communicate between devs and non devs.I ask my clients to draw actor diagrams all the time. It's often better than a long paragraph of text.

I'm not sure how any big team can work without using some UML diagram of some sort. SCRUM boards dont help writing code.

UML is pretty lousy as a formal design language, but it's about the best we have. It's a pretty good communication tool though and a pretty good tool for documenting an existing system for later reference. Not all of the diagram types are equally useful, some are better than others. Sequence diagrams are really useful for example, but use-case diagrams are usually small enough that they aren't necessary.

I think I spent three years in college getting examined on UML diagrams of all sorts. There is so much detail you can put into a UML diagram that means so much, like arrow heads mean class A implements interfface B. I have never seen anyone in work life ever use that much detail. I have done 100s of sketches of class diagrams and sequence diagrams but never have I made one that would fit the rigid rules of UML diagrams.How can there be so many rules for drawing lines between boxes?

I once did create fully compliant UML diagrams for a requirements document. The next day half the team emailed me back asking what all the box types, arrow heads and broken lines meant. Honestly, simple sketches with annotations have served me so much better than following the rigid rules of UML.

Yes ... hierarchical UML state charts are best in class for their niche, sequence diagrams are useful too. I use both for a Firebase abstraction layer: https://github.com/tomlarkworthy/firesafe/wiki/Send-Item (state chart is at bottom)

Sequence diagrams are extremely useful.

The only problem with UML is that it was used as a method of intellectual masturbation by people who love massive class hierarchies. There's a lot of good stuff in UML, the problem is that the people who were attracted to it in the mid 90s were the same people who were poor programmers and were looking for any excuse to avoid writing code. There are the same guys who spent years building up formalisms in tools like Rational Rose and other pseudo-engineering tools.

When used by good programmers to illustrate specific hard-to-reason about components of the system, it is a useful tool. Activity diagrams, sequence diagrams, use case diagrams and communication diagrams are all useful.