¿Cuál es la diferencia entre dude y buddy ?Puedes dar oraciones como ejemplo.

They're both ways of calling people as a replacement for their names.

If for example your friend did something and you are annoyed or angry, you can say "DUDE?!?!", but it's not natural if you use "buddy" in this case because "buddy" is more friendly than "dude". I think "dude" is quite flexible and is used a lot in many situations such as "Hey Dude", "What's up Dude?", "Dude, did you realise how stupid that is?"

I'd use "buddy" when greeting, like "Hey Buddy". I probably wouldn't use it with friends, but maybe with young kids who I know well. You might also hear "Hey kid-o".