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Questions tagged [fiddler]

Fiddler (aka "Fiddler classic") is a free .net based web debugging proxy for Windows, which allows you to log, examine, modify and replay HTTP/HTTPS traffic from your computer.

The tool shows an overview of HTTP(S) requests and details about the selected request(s) - see the screenshot below.

It allows you to inspect both the request and response, filter data that are (un)interesting, as well as modify (by script or manually) and/or replay chosen requests. The request/response list can be also saved and loaded.

Fiddler Classic has been superseded by the commercial non-free software Fiddler-Everywhere.

Fiddler is also available as a .NET library, FiddlerCore, and as a capture-only FiddlerCap tool (useful, for example, for collecting debug traffic data from customers).

Fiddler Classic is a free-to-use tool; requires MS Windows XP or later and Microsoft .NET Framework v4.0 or later. Download page here

Screenshot

enter image description here

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Chrome:The website uses HSTS. Network errors...this page will probably work later

I am developing against localhost. This morning right after I used fiddler I started getting this error on chrome (works correctly in firefox) "You cannot visit localhost right now because the website uses HSTS. Network errors and attacks are…
developer747
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Filter Fiddler traffic

Is it possible to instruct Fiddler to only show me traffic directed to a specific host name? In other words, can Fiddler traffic be filtered for Host?
Lorenzo
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visual studio 2015 vshub is spamming fiddler

I have read: How do I disable VsHub.exe in the system tray? and https://connect.microsoft.com/VisualStudio/feedback/details/1919828/hundreds-of-calls-second-to-vshub-and-browserlink-is-off I would prefer to not disable vshub; I just want it to be…
Greg Netland
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How do I get Fiddler to stop ignoring traffic to localhost?

When using Fiddler to monitor HTTP Requests & Responses in Internet Explorer it ignores all traffic directed to http://localhost.
NotMyself
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How to configure Fiddler to listen to localhost?

I want to monitor HTTP traffic between a process on my local machine and another (server) process, also running on my local machine. How can I configure Fiddler to listen to traffic to and from localhost?
The Light
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Filtering fiddler to only capture requests for a certain domain

I'm not sure how to modify the CustomRules.js file to only show requests for a certain domain. Does anyone know how to accomplish this?
CVertex
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How to use Fiddler to monitor WCF service

I have a WCF service that accepts a complex type and returns some data. I want to use Fiddler to see what the incoming requests to the service looks like. The client is .net console app which uses a Service reference proxy. Is this possible with…
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How do you remove the root CA certificate that fiddler installs

Fiddler helpfully offers to add a unique root CA certificate to intercept HTTPS traffic. Once this certificate has been added, how do you go about removing it?
muzzamo
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Wireshark vs Firebug vs Fiddler - pros and cons?

Recently, I came across an issue where a CGI application is not responding. Symptom is Firefox displaying: Transferring data from localhost... But the thing is I cannot see any traffic from Firebug's Net panel, and the browser just stays on the…
Michael Mao
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fiddler HTTPMethod (GET/PUT/POST/DELETE...) Column

Is there an easy way to add an HTTPMethod (GET/PUT/POST/DELETE...) column to the fiddler display? Found these instructions on the fiddler wiki for adding session variables: cols add "Client IP Address" X-CLIENTIP But HTTPMethod doesn't seem to be…
thamster
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How to display localhost traffic in Fiddler while debugging an ASP.NET application?

How do I display localhost traffic in Fiddler while debugging an ASP.NET application?
Michael Kniskern
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Chrome Doesn't Trust Fiddler Root Certificate

I have Fiddler installed on my machine. I have installed the Fiddler Root Certificate to decrypt HTTPS traffic, but it only works in FF and IE, not in chrome. Chrome does not trust Fiddler's certificate and does not allow me to connect to any…
Citronex
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How do I monitor all incoming http requests?

I need to monitor my application from incoming http POST and GET requests originating from outside and sometimes inside the machine. Is this possible? Been using fiddler but this only does outgoing not incoming (from outside the machine) or have I…
Exitos
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Fiddler - tunnelled http requests to port 443

I've got Fiddler to decrypt https traffic. which works just fine. http://fiddler2.com/documentation/Configure-Fiddler/Tasks/DecryptHTTPS But there are some requests that are shown as "Tunnel to" port 443. Also the protocol of these requests are…
Eranga Dissanayaka
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Fiddler not capturing traffic from browsers

I've been using Fiddler for quite a while, but all of a sudden it no longer captures internet traffic. I'm on Chrome 29 and Fiddler v4.4.5.1. I've checked all filters and rules and nothing is on. I've deleted my rules file, turned on and off…
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