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In DevTools on the Timing tab you can see the following states:

enter image description here _

Except 'Queueing' all states are explained in the DevTools documentation. Do you know what browser does in the Queueing phase ? What queue are we talking about ?

Thx

Additionally it seems that Queueing can take place at the beginning of connection setup and also at the beginning of the 'Request/Response' phase ? enter image description here

Rarar
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    @paul-irish's [answer on emptiness](http://stackoverflow.com/a/31373122/2604748) should cover the information you are looking for. – Garbee Dec 02 '15 at 13:31
  • ok, thank you. It is very informative, does it mean that queueing can take place before the 'Stalled' and 'Request sent' ? – Rarar Dec 02 '15 at 14:25
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    Yes, queues have numerous reasons for occurring and it can occur at multiple points in a request lifecycle. – Garbee Dec 02 '15 at 15:06
  • Possible duplicate of [What the emptiness mean in devtools timings?](http://stackoverflow.com/questions/31104147/what-the-emptiness-mean-in-devtools-timings) – Konrad Dzwinel Dec 09 '15 at 23:53

2 Answers2

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From: Chrome Developers - Network features reference

Queuing

If a request is queued it indicated that:

  • The request was postponed by the rendering engine because it's considered lower priority than critical resources (such as scripts/styles). This often happens with images.
  • The request was put on hold to wait for an unavailable TCP socket that's about to free up.
  • The request was put on hold because the browser only allows six TCP connections per origin on HTTP 1.
  • Time spent making disk cache entries (typically very quick.)

Update from @cyptus comment:

With chrome v76 the network tabs will hide the CORS preflight (OPTIONS) request. The request that triggered this CORS will include the time the (invisible) OPTIONS request took in the queueing timing.

Update from @tamilsweet comment:

To show the CORS preflight follow Chrome not showing OPTIONS requests in Network tab

naXa stands with Ukraine
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Ernesto Campohermoso
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    With chrome v76 the network tabs will hide the CORS preflight (OPTIONS) request. The request that triggered this CORS will include the time the (invisible) OPTIONS request took in the queueing timing. – cyptus Aug 27 '19 at 12:33
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    To show the CORS preflight follow https://stackoverflow.com/questions/57410051/chrome-not-showing-options-requests-in-network-tab – tamilsweet May 19 '20 at 13:54
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Another possibility may be there is a fresh service worker which is trying to install or activate. Keep the service worker url solid among your page visits.

tianjianchn
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