Fiddler for OS X Beta

Latest Fiddler Available for OS X

Mono framework installed


Please download it from

and install it.
If you already have it installed, ensure you’re running the latest version.

If you just installed Mono

/Library/Frameworks/Mono.framework/Versions/<Mono Version>/bin/mozroots --import --sync


cd /Library/Frameworks/Mono.framework/Versions/

以下が表示されたのでバージョン5.10.0 となります。

5.10.0  Current


/Library/Frameworks/Mono.framework/Versions/5.10.0/bin/mozroots --import --sync


Mozilla Roots Importer - version
Download and import trusted root certificates from Mozilla's MXR.
Copyright 2002, 2003 Motus Technologies. Copyright 2004-2008 Novell. BSD licensed.

WARNING: mozroots is deprecated, please move to cert-sync instead.

Downloading from ''...
Importing certificates into user store...
153 new root certificates were added to your trust store.
Import process completed.


The Mono framework has its own trusted root certificates store. Currently (at mono version 4.2.4) this store remains empty after installing Mono on OS X. Fiddler uses the certificates in this store to validate the certificates of the websites visited. So you need to populate this store with a set of commonly trusted root authorities to avoid getting constant certificate warnings by Fiddler. The mozroots tool imports trusted authorities from the Mozilla LXR.



It is recommended that the full path to Fiddler install folder does not contain any Windows path illegal characters. (At present it is possible that some Fiddler functionality, e.g. various file exports or Fiddler Script won’t handle such paths.)



mono --arch=32 Fiddler.exe

The Carbon driver has not been ported to 64bits, and very few parts of Windows.Forms will work properly, or at all Stacktrace:


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