Working as a part time student on an app and until now I thought I was the king of software development.
Well, fuck me and my high horse.

Today the stuff we send from the client to the server didn't arrive, so I asked the backend guy if he could take a look at the packages arriving. He did and told me the data was messed up.
I did only design stuff the last week or so, so I was very confused. After reverting back to one old commit after the other it struck me.
I still don't know how such a dumb mistake could have happened to me, the king of Android apps, but apparently I replaced all occurrences of a specific keyword in just the strings and comments of the whole project. Key became KeyList, so instead of <Keys> my XML contained <KeyList> which made no goddamn sense whatsoever.
Did I mention that we have an important deadline tomorrow? Yeah...

So now I leaned my lesson. Never trust XML.

JK I'm dumb. That's the lesson here.