Charles debugging proxy application. Introduction

This article is a starting point for thread devoted to great tool - Charles Debugging Proxy Application.
Please note: all links herein are direct and safe, not hide any promo-keys, referrals or ads.I just really enjoy using this tool and happy to share information about it.

General information

What is the purpose of Charles

Charles is a web debugging application designed for intercepting and logging the traffic between a client and a server. In general, such an information helps to investigate:

• where (to which hosts) does the client send the requests;
• what is an actual header and content of the requests;
• what is the server’s response;
• what content does the response have;
• when does all this happen (what is a sequence of requests-responses in time).

What does Charles consist from

Charles is a single desktop application. It can be used standalone (w/o network connection) e.g. for reading and analyzing logs, which were saved previously. Application is available in versions for MS Windows (32 and 64 bit), MacOS and Linux (32 and 64 bit).
Add-on for Mozilla Firefox browser is also available. It helps to configure Firefox automatically for been used with Charles.
Charles also has a web-based interface. Literally it means that user may observe Charles as a web page in browser. That may be extremely useful for automation test purposes via Selenium Driver.

How does it work

Briefly – Charles comes an intermediate chain between a client (desktop browser, iOS native application, mobile browser in Android) and a remote server.

Charles uses trust certificates, which allows not only “listen” the exchange between client and server, but also “understand” most of the transmitted information and show it to a user in multiple friendly views.

How can I get and use it

Charles has a full functional trial version. The limitation of trial version is session length not longer than 30 minutes. Also during work in trial a user faces warnings several times per session which lasts several second.
And one more thing, the trial version has a warning that trial will expire in 30 days. Actually for all Charles versions up to 4.1.2 it never happens.
There are no other limitations in using non-registered version of Charles.
Download an up-to-date version for your system on www.charlesproxy.com/download/
Check with your local network administrator or department manager if you have a corporate license key.
To buy a license key, please refer to www.charlesproxy.com/buy/
Charles authors are constantly improving their product and they are doing great! So, it’s really appreciated to buy a license:

Add-on for Firefox is available here: addons.mozilla.org/en-US/firefox/addon/charles-proxy/
Charles is developed by XK72. In case of any questions the developers and founders of Charles may be reached at www.xk72.com/ or via support section of www.charlesproxy.com .
Instructions on installation of the program and setting up a root certificate are available in the Next articles.