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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Fiddler Classic has been superseded by the commercial non-free software Fiddler-Everywhere.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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Use Fiddler with Basic Authentication to access RESTful WebAPI

I have a WebAPI that works without issue. I have tested locally and deployed to my server and configured this service in IIS to use Basic Authentication. I am able to browse to my service and I receive the Authentication challenge I expect and all…
brianhevans
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How to view WS/WSS Websocket request content using Firebug or other?

Is there a way to view the Websocket traffic? Only Websocket headers are visible on the initial handshake. Everything disappears after the response: Connection Upgrade Sec-WebSocket-Accept EQqklpK6bzlgAAOL2EFX/nx8bEI= Upgrade WebSocket I've…
Stevko
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Is there a non-installable version of Fiddler, or equivalent?

One of my clients is currently waiting for his IT department to install Fiddler on his desktop so that he can debug his web application... Apparently his desktop requires IT Admin rights to install anything. Is there a non-installable version of…
Oskar Austegard
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Why Doesn't Fiddler Show Curl Traffic?

Why doesn't Fiddler show curl traffic? Other traffic gets displayed, just not curl. How can I get fiddler to intercept curl traffic?
BSalita
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How to modify a request in Fiddler?

I'm looking for a simple way to intercept a web request and modify the contents of the request (mainly POSTs) using Fiddler. This is to test server-side validation. I have to use Fiddler, however I haven't found a good simple way to do so. There…
Justin
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how to Capture https with fiddler, in java

I am running the following java program in the Eclipse IDE: import java.net.*; import java.io.*; public class HH { public static void main(String[] args) throws Exception { //if i comment out the system properties, and don't set…
Sam Adamsh
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Show request's timestamp in Fiddler?

I received a long Fiddler trace (with a complicated scenario) and need to correlate the requests with application logs. Unfortunately, while Fiddler displays the requests chronologically, it doesn't display the timestamps of the request. To access…
wishihadabettername
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How can I set a cookie in a request using Fiddler?

I need to set a cookie before I issue a request to a Web site using Fiddler. How do I do this?
Jeremy McGee
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Fiddler causes my Internet access to stop working

I have Windows 8.1 installed on my computer and regularly use Fiddler to capture web traffic. Recently, however, when I open Fiddler and have it capture web traffic, my Internet connectivity dies. The error I get when I open IE is "This page cannot…
user1763965
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What is point of SSL if fiddler 2 can decrypt all calls over HTTPS?

I asked a question here a while back on how to hide my http request calls and make them more secure in my application. I did not want people to use fiddler 2 to see the call and set up an auto responder. Everyone told me to go SSL and calls will be…
Landin Martens
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Can a proxy (like fiddler) be used with Node.js's ClientRequest

Can node.js be setup to recognize a proxy (like Fiddler for example) and route all ClientRequest's through the proxy? I am using node on Windows and would like to debug the http requests much like I would using Fiddler for JavaScript in the…
chuckj
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What is the meaning of this fiddler icon?

I got a line in fiddler2 looking like this: ICON # status protocol host url XXX 3 200 HTTP www.myserver.com /images/save.png The icon shown is a forbidden icon like this: Actually i am analizing a loading problem in one of…
Thariama
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How can I trace the HttpClient request using fiddler or any other tool?

I am using HttpClient for sending out request to one of the web api service that I don't have access to and I need to trace the actual request stream getting to the server from my client. Is there a way I can hookup the Fiddler to listen to the…
dhruvin
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How to test which version of TLS my .NET client is using?

I support a .NET site which (amongst many, MANY, other things) talks to remote APIs from supplier systems. We want to upgrade to support TLS 1.2 We're hoping to do so as per this question: Are there .NET implementation of TLS 1.2? But how do I check…
Brondahl
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Hide "Tunnel to" sessions

I try hide sessions generated by social part of Chrome. But hiding of traffic marked as "Tunnel to" in host column not working. Althoungh I successfully hide another sessions based on hostname patterns. if (oSession.HTTPMethodIs("CONNECT")) { …
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