The difference is very slight. For example, if I told you that the buses in Rome are on strike tomorrow, but it was not true, I would say, 'I was kidding', not "I was joking". Joking or kidding can both be used for funny things. For example, 'if you eat carciofi every day you will lose alot of weight', I can say I am kidding or I am joking.

There's no difference.

I'm joking - formal and obsolete. I'm kidding - informal and modern. We barely use the first one but in contrary the second one is being use all the time. In a nutshell there is no difference between those two.

hi

A very subtle difference often you cannot tell the difference. It is a situation where body language tone of voice and familiarity with a person comes into play. Jokes bad irresponsible jokes called pranks can cause harm or injury or death. to kid will never do this to kid is an ancient word comes in and out of fashion been back in fashion for some time now looks likely to stay in fashion. the word is thought to come from behaving like a child (kid) or to be like a young spring lamb (playing in the fields.