Headers toolbar

Using the Headers toolbar, you can:

• Filter the headers in the Response Headers and Request Headers sections.

• Block the domain involved in this request. The domain is added to theBlocking sidebar.

• Resend the request. TheResend button opens a menu with two items:

  • Resend: Resends the request.

  • Edit and Resend: Enables an editing mode, where you can modify the method, URL, request headers, or request body of the request. ClickSend to send the modified request, orCancel to cancel editing.

Request Information

The following information is shown only when the section is expanded:

• Scheme: The scheme used in the URL

• Host: The server involved in the request

• Filename: The full path to the file requested

• Address: The IP address of the host

The following information is shown in both the collapsed and the expanded states:

• Status: TheHTTP response code for the request.

• Version: The HTTP version used

• Transferred: The amount of data transferred with the request

• TheReferrer Policy, which governs which referrer information, sent in theReferer header, should be included with requests. (SeeReferrer-Policy for a description of possible values)

• Blocking: If the request is to a site that is associated with a known tracker, an icon and a message are shown; otherwise, this field is not shown.

Early hints response headers

TheEarly hints response headers section shows the headers provided by HTTP 103 informational response. For each line in the early hints response headers section, a question mark links to the documentation for that response header, if one is available.

ARaw toggle button in the section heading controls whether the headers are shown with formatting, or as plain, unformatted text.

Response headers

The response headers section shows details about the response. For each line in the response headers section, a question mark links to the documentation for that response header, if one is available.

ARaw toggle button in the section heading controls whether the headers are shown with formatting, or as plain, unformatted text.

You can copy some or all of the response header in JSON format by using the context menu:

If you selectCopy, a single key word, value pair is copied. If you selectCopy All, the entire header is copied in JSON format, giving you something like this (after running the results through a JSON validator):

{"Response headers (1.113 KB)":{"headers":[{"name":"accept-ranges","value":"bytes"},{"name":"age","value":"0"},{"name":"backend-timing","value":"D=74716 t=1560258099074460"},{"name":"cache-control","value":"private, must-revalidate, max-age=0"},{"name":"content-disposition","value":"inline; filename=api-result.js"},{"name":"content-encoding","value":"gzip"},{"name":"content-length","value":"673"},{"name":"content-type","value":"text/javascript; charset=utf-8"},{"name":"date","value":"Tue, 11 Jun 2019 13:01:39 GMT"},{"name":"mediawiki-login-suppressed","value":"true"},{"name":"p3p","value":"CP=\"This is not a P3P policy! See https://en.wikipedia.org/wiki/Special:CentralAutoLogin/P3P for more info.\""},{"name":"server","value":"mw1316.eqiad.wmnet"},{"name":"server-timing","value":"cache;desc=\"pass\""},{"name":"strict-transport-security","value":"max-age=106384710; includeSubDomains; preload"},{"name":"vary","value":"Accept-Encoding,Treat-as-Untrusted,X-Forwarded-Proto,Cookie,Authorization,X-Seven"},{"name":"via","value":"1.1 varnish (Varnish/5.1), 1.1 varnish (Varnish/5.1)"},{"name":"x-analytics","value":"ns=-1;special=Badtitle;WMF-Last-Access=11-Jun-2019;WMF-Last-Access-Global=11-Jun-2019;https=1"},{"name":"x-cache","value":"cp1075 pass, cp1075 pass"},{"name":"x-cache-status","value":"pass"},{"name":"x-client-ip","value":"204.210.158.136"},{"name":"x-content-type-options","value":"nosniff"},{"name":"X-Firefox-Spdy","value":"h2"},{"name":"x-frame-options","value":"SAMEORIGIN"},{"name":"x-powered-by","value":"HHVM/3.18.6-dev"},{"name":"x-search-id","value":"esvan0r5bnnwscyk2wq09i1im"},{"name":"x-varnish","value":"766019457, 417549316"}]},"Request headers (665 B)":{"headers":[{"name":"Accept","value":"*/*"},{"name":"Accept-Encoding","value":"gzip, deflate, br"},{"name":"Accept-Language","value":"en-US,en;q=0.5"},{"name":"Connection","value":"keep-alive"},{"name":"Cookie","value":"WMF-Last-Access=11-Jun-2019; WMF-Last-Access-Global=11-Jun-2019; mwPhp7Seed=5c9; GeoIP=US:NY:Port_Jervis:41.38:-74.67:v4"},{"name":"DNT","value":"1"},{"name":"Host","value":"en.wikipedia.org"},{"name":"Referer","value":"https://www.wikipedia.org/"},{"name":"TE","value":"Trailers"},{"name":"User-Agent","value":"Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Firefox/68.0"}]}}

Request headers

The Request headers section shows details about the request headers. For each line in the request headers section, a question mark links to the documentation for that request header, if one is available.

ARaw toggle button in the section heading controls whether the headers are shown with formatting, or as plain, unformatted text.

HTML preview

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

Queued, Started, Downloaded

The following timings are displayed at the top of the Timings tab:

• Queued: When the resource was queued for download.

• Started: When the resource started downloading.

• Downloaded: When the resource finished downloading.

Request Timing

TheRequest Timing section breaks a network request down into the following subset of the stages defined in theHTTP Archive specification:

Server Timing

TheServer Timing section lists any information provided in theServer-Timing header — this is used to surface any backend server timing metrics you’ve recorded (e.g. database read/write, CPU time, file system access, etc.).

The header takes a series of descriptions and durations, which can be anything you like. In the above screenshot for example, the highlighted request’sServer-Timing header contains 4 items —data,markup,total, andmiss.

Service Worker Timing

TheService Worker Timing section lists the information relating to the specific service worker request. The metrics include Startup, Dispatch fetch and Handle fetch.