The QBWC is hardcoded to require SSL (secure sockets layer) on remote domains. This is recommended since it encrypts the information transfer between QuickBooks and Kartris, which may contain sensitive information.

The QBWC will work however with any URL that contains 'localhost', presumably so that developers can test using a local web site. We have therefore coded Kartris to append an unused parameter 'localhost' to URLs, in order to permit operation on a live web site that does not have SSL – for testing purposes for example.

While this means that Kartris/QuickBooks integration will work on a live site without SSL, we would urge store owners to consider the benefits of SSL and not to risk using the feature without SSL. Intuit have hardcoded the use of SSL in for a reason after all.