I am wondering if I should pass my values in URL or in body as JSON object. Which option is better?
Your question is unclear. Are you concerned about convenience or security?
If its convenience, it doens't matter either way. Usually its easier to shape a request body.
If its for security, it doesn't matter too much. The body of the network call is just as easy to read as the URL. If you are concerned about security it is imperative that you use SSL.