Your sentence is not complete. You have to say ' you've got to be kidding!' We can use 'have got to' in the same way as 'have to' to mean 'must' . So, you could also say 'you have to be kidding'.

No. You've got to be kidding!

Hi, I strongly believe that the phrase "You gotta be kidding me" would be more accurate . Same to " I gotta go now " :)

it is correct to use "you have got to be kidding". But people do use "you got to be kidding" in colloquial language.