Video

Meaning 1

You’re joking > to express disbelief,

Context 1

“Someone tried to break into the house yesterday”
“What? When?”
“Middle of the day while I was home!”
“You’re kidding me!”
“No, its true, found him playing with the front window”

Meaning 2

That’s amazing

Context 2

“Guess what! I won that photo competetition!”
“You’re kidding!”
“No! first prize is a camera, I’ll get it next week!”