The request details pane appears when you click on a network request in the request list. This pane provides more detailed information about the request.

Network request details

Clicking on a row displays a new pane in the right-hand side of the network monitor, which provides more detailed information about the request.

The tabs at the top of this pane enable you to switch between the following pages:

  • Headers
  • Cookies
  • Params
  • Response
  • Cache
  • Timings
  • Security (only for secure pages)
  • Stack trace (only when the request has a stack trace, e.g. a script called by another script). This has been available since Firefox 55.

Clicking the icon at the right-hand end of the toolbar closes the details pane and returns you to the list view.


The Headers tab has three main sections:

The top section lists basic information about the request:

This includes:

  • Information about the request
  • HTTP request header
  • Response header

Request Information

  • Request URL
  • Request method
  • Remote IP address and port
  • Status code with question mark icon linking to this is a link for more details about the particular status code, if available, in the MDN documentation of the HTTP headers.
  • An Edit and Resend button to edit and resend the request and
  • A Raw headers button to display the raw request and response headers.
  • The HTTP version used
  • The Referrer Policy, which governs which referrer information, sent in the Referer header, should be included with requests. (See Referrer-Policy for a description of possible values)

You can filter the headers that are displayed.

Response headers

The response headers section shows details about the response. If you hover over a line in the response headers section, a question mark links to the documentation for that response header, if available.

Request headers

The Request headers section shows details about the request headers. If you hover over a line in the request headers section, a question mark links to the documentation for that request header, if available.


This tab lists full details of any cookies sent with the request or response:

As with headers, you can filter the list of cookies displayed. The full list of cookie attributes is shown—see the below screenshot from a Response cookies examples with further attributes shown.

cookies panel in firefox devtools network monitor, showing a number of cookie attributes including samesite

The samesite attribute has been shown since Firefox 62 (bug 1452715).


This tab displays the GET parameters and POST data of a request:


The complete content of the response. If the response is HTML, JS, or CSS, it will be shown as text:

If the response is JSON, it will be shown as an inspectable object:

If the response is an image, the tab displays a preview:


If the response is cached (i.e. a 304), the Cache tab will display details about that cached resource.

These details include:

  • Last fetched: The date the resource was last fetched
  • Fetched count: The number of times in the current session that the resource has been fetched
  • Data size: The size of the resource.
  • Last modified: The date the resource was last modified.
  • Expires: The date the resource expires.
  • Device: The device the resource was fetched from (e.g. "disk").

HTML preview

If the response is HTML, a preview of the rendered HTML appears inside the Response tab, above the response payload.


The Timings tab breaks a network request down into the following subset of the stages defined in the HTTP Archive specification:

Name Description

Time spent in a queue waiting for a network connection.

The browser imposes a limit on the number of simultaneous connections that can be made to a single server. In Firefox this defaults to 6, but can be changed using the network.http.max-persistent-connections-per-server preference. If all connections are in use, the browser can't download more resources until a connection is released.

DNS resolution Time taken to resolve a host name.
Connecting Time taken to create a TCP connection.
Sending Time taken to send the HTTP request to the server.
Waiting Waiting for a response from the server.
Receiving Time taken to read the entire response from the server (or cache).

It presents a more detailed, annotated, view of the timeline bar for that request showing how the total wait time is split into the various stages:


If the site is being served over HTTPS, you get an extra tab labeled "Security". This contains details about the secure connection used including the protocol, the cipher suite, and certificate details:

The Security tab shows a warning for security weaknesses. Currently it warns you about two weaknesses:

  1. Using SSLv3 instead of TLS
  2. Using the RC4 cipher

Stack trace

Stack traces are shown in the Stack Trace tab, for responses that have a stack trace of course.

Network Monitor Features

The following articles cover different aspects of using the network monitor:

Document Tags and Contributors

Contributors to this page: irenesmith, dhyey35, mdnwebdocs-bot, jbrandes
Last updated by: irenesmith,