If I have more than one mapping to the same request url, what is the criteria to choose the response?

WireMock will scan through the list of stubs attempting to match the request to each stub’s match criteria (which can consist of path, query, headers, cookies, form parameters and body) and will return the response for the first one matched. Newly inserted stubs take precedence over older ones, but the priority field can be used to override this. Alternatively if you want state, rather than purely the request to determine the response you can use the Scenarios feature.