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The Fiddler User Interface


The Web Sessions List

The Web Sessions list contains the list of HTTP Requests that are sent by your computer.  You can resize and reorder the columns in this list for your convenience.  You can also sort this list by clicking on the column header.

Certain key information is available in this list, including:

  • # - An ID# of the request generated by Fiddler for your convenience
  • Result - The Result code from the HTTP Response.  Learn more...
  • Protocol - The Protocol (HTTP/HTTPS/FTP) used by this session
  • Host - The hostname of the server to which the request was sent
  • URL - The path and file requested from the server
  • Body - The number of bytes in the Response body
  • Caching - Values from the Response's Expires or Cache-Control headers
  • Process - The local Windows Process from which the traffic originated
  • Content-Type - The Content-Type header from the Response
  • Custom - A text field you can set via scripting.  Learn more...
  • Comments - A text field you can set from scripting or the session's context menu

In Fiddler v2.2.0.5 and later, you can add new columns of your choice.

The default text coloring of the Session entries derives from the HTTP Status (red for errors, yellow for authentication demands), traffic type (CONNECT appears in grey), or response type (CSS in purple, HTML in blue; script in green, images in grey).  You can override a session's text color using the ui-color flag in FiddlerScript.

Each session is marked with an icon for quick reference:

Request is being sent to the server
Response is being read from the server
Request is paused at a breakpoint
Response is paused at a breakpoint
HEAD icon Request used HTTP HEAD method; response should have no body
POST icon Request used HTTP POST method
Lock icon Request used HTTP CONNECT method; this establishes a tunnel used for HTTPS traffic
Response was HTML
Response was an image
Response was a script
Response was Cascading Style Sheet
Response was XML
JSON icon Response was JSON
Audio icon Response was an audio file
Video icon Response was a video file
Silverlight Response was a Silverlight applet
Flash Response was a Flash applet
Font icon Response was a font
Generic successful response
Response was HTTP/300,301,302,303 or 307 redirect
Response was HTTP/304: Use cached version
Response was a request for client credentials
Response was a server error
Session was aborted by the client, Fiddler, or the Server.

Interacting with Sessions

If you right-click one or more sessions, a context-menu appears:

Tip: You can add to this menu using the ContextAction feature of FiddlerScript.  Learn more...

On the Copy menu:

  • Session - Copy the raw session(s) to the clipboard in plaintext and colorized HTML format
  • Just URL - Copy the hostname + URL path
  • Headers Only - Copy the request and response headers to the clipboard in plaintext and colorized HTML format
  • Full Summary - Copy all columns in the session list to the clipboard in plaintext and HTML suitable for pasting into Excel
  • Terse Summary - Copy the request URL and the response Status to the clipboard

On the Save menu:

  • Session > In ArchiveZIP - Creates a .SAZ archive containing all selected requests & responses, plus an index page. 
  • Session - Create a text file containing the request followed by the response
  • Headers Only - Create a text file containing the request and response headers
  • Full Request - Create a text file containing the request headers and request body
  • Request Body - Create a file containing the body of the request (generally HTTP POST data)
  • Full Response - Create a text file containing the response headers and response body
  • Response Body - Create a file contain the body of the response (often HTML or an image)


The AutoResponder tab allows you to return locally stored content instead of forwarding requests to the server.  Learn more...


The Inspectors tab allows you to view the contents of each request and response, in a variety of different formats.  You can develop custom Inspectors using .NET.


The Filters tab enables you to quickly filter out traffic that is not of interest. Learn more...


The Timeline Tab shows the transfer timeline of selected HTTP Sessions. Learn more...


The QuickExec box below the session list allows you to execute commands and search your traffic. Learn more...

QuickExec Box

Request Composer

The Request Composer allows you to craft custom requests to send to the server.  You can either create a new request manually, or you can drag and drop a session from the Web Sessions list to create a new request based on the existing request. Learn more...

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