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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Fiddler Classic has been superseded by the commercial non-free software Fiddler-Everywhere.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 can easily decode responses - how to make this automatic?

In Fiddler I have many responses which I like to view raw. For each one Fiddler says "Response is encoded and may need to be decoded before inspection. Click here to transform." I want not only the current one, but all responses to always be…
Daniel Williams
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Show sent POST Values with Fiddler..How do i do that?

I make some requests to a site and i want to see, what kind of variables has been sent to the server.. May be its possible with fiddler but i can't figure it out, how to do it..
user877167
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fiddler2 unable to generate certificate

I'm using Fiddler2 (or trying) to capture SSL traffic for a windows desktop gadget hitting an https web service. It used to work, and then it stopped a couple days ago, always with this error: --------------------------- Unable to Generate…
Ben Collins
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WebApi HttpClient not sending client certificate

I am trying to secure my RESTful WebApi service with ssl and client authentication using client certificates. To test; I have generated a self signed certificate and placed in the local machine, trusted root certification authorities folder and i…
Tronneh
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How to use NGINX as forward proxy for any requested location?

I am trying to configure NGINX as a forward proxy to replace Fiddler which we are using as a forward proxy. The feature of Fiddler that we use allows us to proxy ALL incoming request to a 8888 port. How do I do that with NGINX? In all examples of…
Arman Bimatov
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How to reset filters in Fiddler?

I am trying to set up some filters in Fiddler and I do not know how to reset them, if I made a mistake. An example of a session: Unfiltered status: Applying a wrong filter (which will not match anything): I end up with an empty session list (which…
WoJ
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Why does my C# gzip produce a larger file than Fiddler or PHP?

If I GZip this text: Hello World through C# using this code: Stream stream = new MemoryStream(Encoding.Default.GetBytes("Hello World")); var compressedMemoryStream = new MemoryStream(); using (var gzipStream = new…
Martin Harris
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Configuring Fiddler to use company network's proxy?

I'm trying to get Fiddler to work with my company's proxy. Every external request is returning 407. So far I've tried adding oSession.oRequest["Proxy-Authorization"] = "YOURCREDENTIALS"; to the customized rules where I used my USERNAME:PASSWORD in…
Ryan Peters
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check POST request with Fiddler

How can I use Fiddler to check the response from a web server. I could easily check the GET method by pasting the url to the field in Request Builder and get the response back in xml/json. There is an option POST, however I don't know how can I pass…
Nghia Nguyen
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In Fiddler how can I see the list of filters added by "Filter Now"?

In Fiddler you can: Right click on a session Select Filter Now Show/hide domain/process These filters do not show up in the Filters tab. Mine is empty: How do you see the list of filters you've added? How a filter you've added?
awilkinson
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How to Remove / Disable local map in charles proxy

How do I Remove / Disable local map in charles proxy? I can see that you can disable it when you go to the "Tools" section but how do I remove the file mapping completely?
user1175906
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Converting cookie string into Python dict

In Fiddler, I captured an HTTPS request with the following cookie string sent from the client (visible in Inspectors > Raw): Cookie: devicePixelRatio=1; ident=exists; __utma=13103r6942.2918; __utmc=13103656942;…
Peter Richter
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Injecting JavaScript into head element of website using Fiddler

I was thinking of using Fiddler for the following purpose... I have a JavaScript based service I want to demonstrate to potential clients. In order to show them what their website could look like if they install (i.e. include) my script, I want to…
odedbd
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Fiddler not capturing HTTP requests from Java Application

I am currently writing a java application that uses HTTP POST to upload a csv file and a few other parameters to a server. The server keeps returning 500 errors to my application and I would like to view the HTTP request in Fiddler so I can see the…
Andrew
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Fiddler doesn't decompress gzip responses

I use Fiddler to debug my application. Whenever the response is compressed by server, instead of decompressed response, Fiddler shows unreadable binary data: /* Response to my request (POST) */ HTTP/1.1 200 OK Server: xyz.com Date: Tue, 07 Jun 2011…
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