Spike supports HTTPS connections using the CONNECT method.

CONNECT is a standard http feature which uses HTTP as an opaque tunnel to transmit information from/to an HTTPS service. It is not a man-in-the-middle scheme, and the intermediary (here, Spike) does not see the contents of the HTTPS request or response. If your application supports CONNECT (as many HTTP clients do), no special work is required to connect it to Spike.