Fiddler Logo Fiddler book image Get the NEW book!
RSS Icon download iconGet Fiddler! Addons Help & Documentation Developer Info Discuss Contact

Fiddler How-Tos

Q: How do I create a Session Archive Zip (SAZ) Traffic archive?

A: Start Fiddler. Use your client or browser to generate some HTTP/HTTPS traffic.

Click File > Save > All Sessions... and save the traffic to a .SAZ file.


Q: How do I see traffic to http://localhost or

A: Read this article. Or upgrade to IE9.


Q: How do I configure Fiddler and IE9 to indicate why a given HTTP Request was made?

A: Read this article.

Enable Download-Initiator tagging.

cols add @request.Accept
cols add @request.X-Download-Initiator

FiddlerObject.UI.lvSessions.AddBoundColumn("Accept", 50, "@request.Accept");

FiddlerObject.UI.lvSessions.AddBoundColumn("Reason", 50, "@request.X-Download-Initiator");


Q: How do I see the HTTPS traffic-- I only see a "CONNECT" tunnel?

A: HTTPS Traffic decryption is disabled by default. Learn more about decrypting HTTPS traffic with Fiddler2.


Q: How do I attach a client certificate?

A: Fiddler and later support client certificates.  See Attaching Client Certificates for more information.


Q: How do I configure my Windows client to trust the bogus root to avoid error messages and enable logon to services like Passport?

A: This is not a recommended configuration.  You should never make this configuration change on a non-Test machine.

  1. Visit a HTTPS site with Fiddler2 running, ensure that you see the Certificate Error warning page
  3. Drag the DO_NOT_TRUST_FiddlerRoot certificate to the Trusted Root Certification Authorities folder

You can make a similar configuration change for Firefox and other clients that do not use the Windows Certificate store; use the appropriate Options dialog in the browser.

Mozilla Firefox Certificate Configuration