Last Updated: 13 Apr 2021 05:41 by ADMIN

MacOs, Fiddler Everywhere 10, Cisco AnyConnect.

Here's the workflow...

In the morning, Cisco VPN isn't connected.  All traffic is blocked by design.  Attempt to start Fiddler Everywhere.  WON'T START because it can't login.  What is this new requirement to login?  If I don't start Fiddler before the VPN, no traffic ever logs.  If i don't start the VPN, Fiddler won't start.  A bit of a cartch-22, ya think?

Somehow I bypass the VPN (Don't tell corp security) and get logged-in.  Fiddler is up.  Start the VPN. Get some work done.  Shiny new UI!  Still can't drag-drop from inspector to composer?  Damn.

At some point the Fiddler login EXPIRES.  Why does it expire?  What do I even need a login for?  At this point ALL TRAFFIC fails, since Fiddler was the system proxy.  All work stops.  Now I need to stop Fiddler, Stop the VPN, attempt to start Fiddler again....oh wait, can't login because the VPN is down...  here we go again.

This is all a serious waste of time.  I can see registering Fiddler so you know who your users are.  What's with the REQUIREMENT to have a login, and why does it expire?  It kinda makes Fiddler useless.

Please remove the requirement to login to an account before being able to use Fiddler Everywhere.




Last Updated: 29 Mar 2021 14:51 by ADMIN
Created by: Scott
Comments: 1
Type: Feature Request

I am testing an api that uses basic auth.  I am trying to use the composer to hit the API.  The existing suggestion is to build the authorization header by hand, but I would suggest that the URL field should be able to handle any URL that a browser or CURL can handle, and so I think it should be able to handle basic auth syntax in the URL, for example:


Currently it takes the user and password and separators and sends the whole thing to DNS ("myUser:p@330rd@someserver.com").  Even if it ignores the username and password (and why would you) it should parse them out before sending the hostname to DNS.  I would be OK with it building the authorization header and removing it from the URL, but I would rather it handle that behind the scenes and leave the URL the way I pasted it in.

Last Updated: 07 Mar 2021 11:36 by ADMIN
Created by: Chris
Comments: 2
Type: Feature Request
I want the ability to search captured URLs and the contents of individual requests.
Last Updated: 02 Mar 2021 14:38 by ADMIN


When I try to trusst the fiddler root certifficate, I get the message "not successfull" and see a line like this in the logfile:

[2021-03-01 16:29:48:866] [Information] [Fiddler] Error when trying to check if certificate is trusted: '.', hexadecimal value 0x00, is an invalid character. Line 304, position 38.

I also tried to trust the certificate by hand via the keyring utility.

What can I try?



Won't Fix
Last Updated: 08 Dec 2020 15:02 by ADMIN

Not sure if this is a bug, but every other telerik product including previous fiddler worked with my telerik login.


I'm not behind a VPN. 

  1. I just downloaded Fiddler Everywhere,
  2. ran it,
  3. tried to sign in and it gives "user does not exist".

This is using the same credentials I used to login to Telerik to write this ticket.

I couldn't find any documentation saying I need a separate account.

Feel free to close or push to Feature Request if this is intended behavior.

Last Updated: 05 Nov 2020 15:19 by ADMIN

I'm unable to connect to "gateway.icloud.com" when Fiddler is open and decrypting HTTPS traffic.

This is Fiddler Everywhere 0.10.0 on macOS 10.15.5.

To reproduce:

Open Fiddler and make sure it's decrypting HTTPS traffic.

Open any browser and go to https://gateway.icloud.com/

Expected result: Page loads (it's blank. This is normal.)

What actually happens: fiddler.network.https> HTTPS handshake to gateway.icloud.com (for #820) failed. System.Security.Authentication.AuthenticationException The remote certificate is invalid according to the validation procedure.


Same thing happens on https://configuration.apple.com/

Last Updated: 04 Nov 2020 12:34 by ADMIN

Currently, Fiddler Everywhere just hard-fails on any invalid SSL certificate. More annoyingly, it doesn't explain why the certificate is invalid.


Fiddler Everywhere should:

1. Allow overriding a certificate error (possibly hide this behind an option)

2. Explain what caused a certificate error

Need More Info
Last Updated: 28 Oct 2020 06:59 by ADMIN
Live Traffic stays paused. It does not unpause when toggled, and the Root Certificate and HTTPS traffic capture are enabled.
Need More Info
Last Updated: 27 Oct 2020 06:51 by ADMIN



When starting Fiddler Everywhere version 1.1.1, I get an exception in the log file.

Fiddler does not cappture any traffic.


Do you know this problem?

How can I solve it?


Best regards!

Need More Info
Last Updated: 25 Oct 2020 15:32 by ADMIN
Created by: Kaitlyn
Comments: 3
Type: Feature Request

I am unable to capture any traffic when connected to my company's VPN (Pulse). With so many people working from home these days, Fiddler Everywhere is positively useless without the ability to use it with a VPN. A few details about my setup:

* I am working on a Mac running Catalina 10.15.7.

* Fiddler Everywhere captures traffic just fine when I am not connected to the VPN, but as soon as I turn it on, no new traffic shows up. When I disconnect the VPN, I immediately see it capturing regular traffic again.

* I cannot connect to my VPN while running Fiddler Everywhere. My VPN Client just spins until it times out when trying to connect with Fiddler running.

* I tried following the instructions for working with Cisco VPN (even though I am using a different VPN) here: https://docs.telerik.com/fiddler-everywhere/knowledge-base/configure-vpn-with-fiddler, but it didn't work. I wasn't able to follow the instructions perfectly anyways, since I can't connect to my VPN while Fiddler is running. But I tried shutting down Fiddler after Step 4, and then restarting it after Step 5. It didn't work.

Please fix this problem! I really liked using Fiddler on Windows, and there really isn't another good comparable product out there for Macs that I have found!

Under Review
Last Updated: 02 Oct 2020 06:45 by ADMIN

There's not really much more information, this occurred on both version 1.0 and 1.1. When I get an emailed fiddler trace (we ask clients for traces regularly), it opens a web page redirect https://redirect.getfiddler.com/open-fiddler.html#snapshotShared-<guid>, which opens the app, and at the top of the app says "Unexpected error" with seemingly no other information. I've tried this on multiple email requests, same effect.


Also on MacOS Catalina v10.15.6

Last Updated: 24 Sep 2020 12:59 by ADMIN
Created by: san
Comments: 13
Type: Feature Request

I am trying to login to fiddler anywhere on Ubuntu.  But since the system is behind proxy, while logging into proxy, i get network error.

I have configured the proxy in env variables as well as network settings >proxy, but it does not work.

Please provide a way to configure the corporate proxy for fiddler everywhere before login


Last Updated: 16 Sep 2020 13:44 by ADMIN

Steps to reproduce:

  1. Post a 69k request to a web api (encoded JSON data) via browser.
  2. Inspect request data in Text and Raw fields.
  3. Observe that the data is truncated in the middle of a property name (not a null char).

Example data posted (snippet with middle section excerpted):


There is much more data that should occur after the property "immediatePatientSafety".  There does appear to possibly be additional fields presented in the Web Form inspector although some of the values are truncated and have an ellipsis (...) following those lines, so I believe that the tool is capturing the data but will not make it visible or available in the Text or Raw Inspectors.

No option exists to configure the amount of request data that is captured or to cause the Inspector to "show more" data.

I need to be able to see the full text request to troubleshoot an issue with the back-end application.

I need the data available in the Text or Raw inspector so that I can cut and paste it out for external processing and discussion with the developers.

I noted that a separate bug report has been issued for a missing "show more data" option on large response records.




Last Updated: 22 Aug 2020 02:10 by Tim

Fiddler for Windows allowed you to add custom columns to Web Sessions list. 

Fiddler Everywhere needs this option so I can add in a column to show the IP address of the server being connected to.

Can these methods be added into Fiddler Everywhere:

  1. https://docs.telerik.com/fiddler/knowledgebase/fiddlerscript/addcolumns
  2. https://docs.telerik.com/fiddler/Observe-Traffic/Tasks/ConfigureColumns 
Last Updated: 14 Aug 2020 09:21 by ADMIN

Latest version of Fiddler (v0.10.0) and Android Emulator is not proxying the connections properly.

I have Fiddler Everywhere running and know it is working when I can send requests through Postman and see them show up in Fiddler properly.

However, if I set up the Android Emulator through Android Studio, and set the proxy to be Fiddler, connections do not fully reach the backend service I am sending requests to. All that shows up in Fiddler is




HTTP/1.1 200 Connection Established
FiddlerGateway: Direct
StartTime: 16:12:05.141
Connection: close

The service is running on my local host machine ( on port 5000.

If I close Fiddler and run charles-proxy, then set the Android Emulator to use that as the proxy, I see the full request, my service responds, and I see the response in Charles.

Last Updated: 03 Aug 2020 13:20 by ADMIN
Scheduled for FiddlerCore Release

Hi there,

I've successfully setup fiddler-everywhere 0.4.0 and am able to sniff traffic to various websites on my linux (Ubuntu 18.04) laptop. However some https sites are not working - fiddler-everywhere severs the connection at the SSL handshake phase. These same sites work in the windows version of Fiddler (v 5.0.20192.25091 - built 04 June 2019) however.

What is the status of the SSL support in fiddler-everywhere vs windows Fiddler?

Example site that fails over https:

Example site that works over https:

Fiddler captures for absa.co.za


CONNECT www.absa.co.za:443 HTTP/1.1
Host: www.absa.co.za:443
Connection: keep-alive
User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.142 Safari/537.36

A SSLv3-compatible ClientHello handshake was found. Fiddler extracted the parameters below.

Version: 3.3 (TLS/1.2)
Random: 1F 0E B0 54 5D 66 42 82 C9 A8 A6 D5 8F C2 F0 C6 A8 16 0C 8E 14 45 F2 B4 B5 95 92 66 B6 53 D6 F4
"Time": 2015/01/09 19:21:35
SessionID: empty
	0x5a5a		empty
	server_name	www.absa.co.za
	extended_master_secret	empty
	renegotiation_info	00
	elliptic_curves	unknown [0xBABA), unknown [0x1D), secp256r1 [0x17], secp384r1 [0x18]
	ec_point_formats	uncompressed [0x0]
	SessionTicket	empty
	ALPN		h2, http/1.1
	status_request	OCSP - Implicit Responder
	signature_algs	sha256_ecdsa, Unknown[0x8]_Unknown[0x4], sha256_rsa, sha384_ecdsa, Unknown[0x8]_Unknown[0x5], sha384_rsa, Unknown[0x8]_Unknown[0x6], sha512_rsa, sha1_rsa
	SignedCertTimestamp (RFC6962)	empty
	0x001b		02 00 02
	0xeaea		00
	[5A5A]	Unrecognized cipher - See http://www.iana.org/assignments/tls-parameters/
	[002F]	TLS_RSA_AES_128_SHA
	[0035]	TLS_RSA_AES_256_SHA




HTTP/1.1 200 Connection Established
FiddlerGateway: Direct
StartTime: 10:28:40.706
Connection: close

fiddler.network.https> HTTPS handshake to www.absa.co.za (for #329) failed. System.IO.IOException Unable to read data from the transport connection: Connection reset by peer. < Connection reset by peer

Last Updated: 03 Aug 2020 07:20 by ADMIN

Colleagues, please add an essential feature of Fiddler Classic called Automatic breakpoints


I'm sure that a bunch of people will migrate to Fiddler Everywhere if you implement this



Last Updated: 31 Jul 2020 08:20 by ADMIN
Created by: qiao
Comments: 1
Type: Bug Report

the logs:


 ~/soft  ./fiddler-everywhere-0.11.0.AppImage 

[8989:0727/220513.696997:FATAL:setuid_sandbox_host.cc(157)] The SUID sandbox helper binary was found, but is not configured correctly. Rather than run without sandboxing I'm aborting now. You need to make sure that /tmp/.mount_fiddle4WxzEm/chrome-sandbox is owned by root and has mode 4755.
[1]    8989 trace trap  ./fiddler-everywhere-0.11.0.AppImage


the environment:

Linux pc 5.3.0-3-amd64 #1 SMP deepin 5.3.15-6apricot (2020-04-13) x86_64 GNU/Linux
Last Updated: 15 Jul 2020 09:54 by ADMIN

With Fiddler on Windows an imported HAR file would load into a new window

Current Fiddler Everywhere appends the HAR file into the current window you have open. 

For example, I see my HAR import and it gets appended into the "Live Traffic" session. It should import into a new window like the existing windows version does.



1 2 3 4