cURL is an easy-to-use client for HTTP, HTTPS, and a whole host of other applications. For, a sample query against our API, see below.
curl -k -u username:password https://your_server/webacs/api/v1/data/InventoryDetails
Note that -k allows cURL to accept non-trusted connections (if you install a certificate onto your server, you can remove the "-k" switch to improve security).