I built CollabUML after the need to work on designing systems with my peers,
instead of screensharing, it's simpler to go into a website and start collaborating,
it saves bandwidth which can be a problem sometimes, and it allows your peers to do
edits instead of just telling you want to modify.
After thinking a bit and talking with people, looks like it can be useful for system design interviews.
I'm still thinking how to evolve it, if you have any ideas, let me know.
Be aware that anyone can go to any board, hence, avoid placing private information.
Looks exactly like the  Scratch programming language IDE from MIT.
Hopefully I'll apply this and other changes in the following days.
Some improvement suggestions:
* Implement shareable URLs (the session name should be in the URL).
* Don't immediately prompt a session name but explain the purpose of the website.
* Link the PlantUML documentation.
Instead of prompting for input, use URLs like http://collabuml.com/s/sessionName (the /s is just to give you some flexibility in the future, should you want to add other URLs to the site), or alternatively, for pure client-side, you could do http://collabuml.com/#sessionName.
For an example of how to do this using a landing page, check https://meet.jit.si/.
If you don't want a landing page, then when someone visits http://collabuml.com/ (with no session name) just immediately do a 302 redirect to a new randomly-generated "session name" URL. If a user wants to join an existing session, they need to use the URL directly (most likely clicking on a link the other person shares with them).
I just pushed a minor update to use the url for the session names.
CollabUML -> You ++: Welcome to CollabUML, The collaborative UML editor
return Sounds good, but How do I use it?
CollabUML --> You : Just share the url with anyone
CollabUML --> You : and start collaborating
CollabUML -> You ++: It's very handy for designing systems with your peers
return How does it works?
CollabUML -> You ++: It's powered by https://plantuml.com \nBe sure to check their docs to see the wonderful things you can do\n Just like this sequence diagram
A cookie associated with a cross-site resource at http://220.127.116.11/ was set without the `SameSite`
attribute. It has been blocked, as Chrome now only delivers cookies with cross-site requests if they are
set with `SameSite=None` and `Secure`. You can review cookies in developer tools under
Application>Storage>Cookies and see more details at https://www.chromestatus.com/feature/5088147346030592
I'm surprised as I and other users can run the app smoothly on Chrome.
******NOTE: There is currently a bug affecting Mac OSX and iOS
which causes SameSite=None cookies to be inadvertently treated
as SameSite=Strict and therefore not sent with cross-site
requests. (See https://bugs.webkit.org/show_bug.cgi?id=198181)
Until this is fixed, SameSite=None may not work properly on
Another cause could be a middle-man (like your ISP), as the site runs on http now.
The goal is to eventually let you choose a name and display who edited which pieces on the text.
It very likely depends on which browser you are using and it's resources (like the network speed), on wifi, it works on my phone on the Opera Mini. Firefox, and Chrome, while using Android.
Android mobile with Firefox. There is a small one centimeter tall picture at the bottom that's the diagram failing to render I suppose?
If you like, send me an email (find it on my github) so that I can make sure the issue gets fixed.
Thanks for the patience.