Recently I have been working a lot with ElasticSearch and when debugging on localhost, my requests do not show up in fiddler.
Normally the trick to solving this is changing from http://localhost:9200 towards http://ipv4.fiddler:9200 or http://ipv6.fiddler:9200, which is really not a good solution, because the moment I close Fiddler, my code stops working as the proxy address no longer resolves.
A co-worker at my current client had a previous job at an internet service provider and taught me a wonderful trick for this! Simple add a fullstop, like so http://localhost.:9200.
Simply by seeing the fullstop, your computer will automatically route the traffic through the DNS, which forces it to go via Fiddler (if Fiddler is running), and if Fiddler is not running, the DNS will resolve it as a regular localhost call. You get the best of both worlds!
Short blog post, but an extremely useful tip!