Capture Time To First Byte using curl

Rai    Linux     calculate, check, curl, download, load time, test, time to first byte, ttfb, website

Working with websites is equivalent to non-ending website testing. Checking the speed of the site itself is not a new thing to check when doing performance diagnostics. And I found out that curl can calculate the speed of a website, from the initial connection time, to the time the first byte is downloaded, up to the total time the site has finished loading.

Here is a sample command using curl:

curl -o /dev/null -w "Connect: %{time_connect} TTFB: %{time_starttransfer} Total time: %{time_total} \n" http://inserturl.here

This command will output this:


[root@rai01 ~]# curl -o /dev/null -w "Connect: %{time_connect} TTFB: %{time_starttransfer} Total time: %{time_total} \n" http://pinoytux.com
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 --:--:-- 0:00:01 --:--:-- 0
Connect: 0.268 TTFB: 1.528 Total time: 1.528

Looks like my website is fast

The first data is the Connect time, which means this is how long it took for the curl to connect to the website.
Connect: 0.268

The second data is time when the first byte was received, Time To First Byte (TTFB).
TTFB: 1.528

The last data is the total time for the site to finish loading.
Total time: 1.528

You can also turn off the progress bar by adding the -s switch to the command.

From: http://www.unquietdesperation.com/2009/03/19/time-to-first-byte-with-curl/

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