Actually, that's the upside of the scripting diagrams since they mostly use the same/compatible language:
plantuml.com
sequencediagram.org
websequencediagrams.com
http://bramp.github.io/js-sequence-diagrams/
....
..
so, it is rather "future safe" since all of them are hardly going to die of. I think it is plant UML that started the syntax but put it out there without license so that's why it is spreading.
sequencediagram.org is the only one of them where you can generate the script by drawing by hand though...