The current version of Fiddler Everywhere depends entirely on the business model that applies different subscription plans through license verification. Account verification is a must so that the clients could receive the perks of the chosen subscription plan. That said, at this moment, having active internet connectivity is a mandatory requirement, and the team is not planning on providing an alternative option.
Alternatively, for scenarios where you need to capture localhost traffic (and no active internet connection is present), you could use Fiddler Classic (Windows only) or Fiddler Jam (on any Chromium browser).
Marschj
I understand that Fiddler is a paid product now, but please provide a way for it to run offline (even if there is a time limit in days or something). When I'm using it where the server and client are on my machine, but I don't happen to have an internet connection (traveling/restrictive vpn connection/etc), I still need to be able to use it.