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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Fiddler Classic has been superseded by the commercial non-free software Fiddler-Everywhere.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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Fiddler - Decrypt Android HttpsUrlConnection SSL traffic

I've spent countless hours trying to decrypt Android SSL traffic via Fiddler for HttpsUrlConnection with very little success. How do I reliably configure Fiddler to decrypt SSL traffic from an Android app using HttpsUrlConnection? Here are my…
Steven
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Why Http request with Fiddler is blazing fast

I wrote a multithread program in c# that crawls a web site, but when I started Fiddler in the background request completed 12x faster, it is really strange for me and when I close Fiddler download rates slows downs. how it is possible please help,…
Ehsan
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Using Fiddler to check IIS Compression

How do I see if IIS Compression is working using Fiddler? I have a page that, when viewed through Port80Software or GID Network's tool it appears to be coming across compressed. However, when I watch the call in Fiddler, I see the 'Accept-Encoding:…
Chris Burgess
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How to get Fiddler to filter specific localhost ports

In a reverse of the usual request of how do I get Fiddler to capture requests to localhost, how do I stop it getting specific ports? Since installing the IE 9 RC, I'm getting loads of requests to Mesh appearing…
SteveC
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How to filter Fiddler traffic by request method?

Fiddler is capturing a lot of HTTP OPTIONS calls, which I have no interest in. Is it possible to ignore these and only see GET and POST?
Buh Buh
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Cannot capture jmeter traffic in fiddler

I created a JMeter recording. But when I start the Test, I don't see any request going in Fiddler. I changed the port number in Fiddler to 8080, that I am using in JMeter. Steps: Create a Thread Group Add Http Request to the Thread Group and…
kedarp
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How to POST XML into MVC Controller? (instead of key/value)

Using Fiddler I can pass in the body someXml=ThisShouldBeXml and then in the controller [HttpPost] public ActionResult Test(object someXml) { return Json(someXml); } gets this data as a string How do I get fiddler to pass…
punkouter
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Ajax post being aborted by firefox (not seen in Chrome or IE)

When using firefox, an ajax post request i have is being reported as aborted in firebug. The ajax post works fine in IE and Chrome. It is not a cross domain request. I tried looking at the issue using fiddler, and when fiddler is capturing web…
FiveTools
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Fiddler add binary file data to POST

I'm try to add binary file data directly to the request body of a POST call so I can simulate a file upload. However, I tried setting a 'before request' breakpoint and using 'insert file' but I couldn't seem to get that to work. I also tried to…
Oliver
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Httpwebreqest works with Fiddler On otherwise Timeout

I am getting a weird error. I have setup a script that works perfectively when Fiddler is open - it downloads a report from a website using httpwebrequest and everything works fine! HOWEVER it only works when Fiddler is open ? When fiddler isnt…
Thomas
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Fiddler not capturing traffic from .Net Core

I have a console app that calls a number of 3rd party services via HTTP/HTTPS that was originally written to run under the .Net Framework. Fiddler works fine with that version of the app, capturing all of the HTTP and HTTPS traffic. I ported the app…
Mike Moore
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Process Filtering with Fiddler

Is there a way to filter out certain processes in Fiddler? Its very noisy currently, and I don't want it to show just one process.
Jordan
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Is it 'safe' to permanently trust the Fiddler root certificate?

I'm looking to inspect HTTP traffic sent and received by a WFC client using Fiddler. To do this I've added the Fiddler Root Certificate to the Windows certificate store. My question: is there are any risk of leaving this certificate in the Windows…
Dan Stevens
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Why is this web api controller not concurrent?

I have a Web API Controller with the following method inside: public string Tester() { Thread.Sleep(2000); return "OK"; } When I call it 10 times (Using Fiddler), I expect all 10 calls to return after ~ 2 seconds. However the calls return…
Elad Katz
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How to check for websocket connections?

Some websites use websockets. How is it possible to check what socket connections are open and on what ports they are open? I basically wants to browse to a website and be able to monitor which websocket connections it opens. Should I use a sniffer…
Kasper Hansen
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