Mono framework installed

すでに導入済みであればこれはスキップ

Please download it from
http://www.mono-project.com/download/#download-mac

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

バージョンを調べる

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

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

バージョンに合わせて以下コマンドを打ちます。

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

結果

Mozilla Roots Importer - version 5.10.0.0
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 'https://hg.mozilla.org/releases/mozilla-release/raw-file/default/security/nss/lib/ckfw/builtins/certdata.txt'...
Importing certificates into user store...
153 new root certificates were added to your trust store.
Import process completed.

解説ブログには以下のような注意書きがありました。

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.

fiddler-mac.zip

fiddler-mac.zipを解凍して出てきたフォルダを書き込み権限があるところへ移動

Windowsパスと同じようなフォルダ構成にしてる場合には（あるのか？）Fiddlerがうまく動作できないようです。

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.)

Fiddlerの実行

ターミナルで配置したフォルダに移動します。
以下のコマンドを打ちます

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:

32bit