How do I measure request and response times at once using cURL?

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I have a web service that receives data in JSON format, processes the data, and then returns the result to the requester.

I want to measure the request, response, and total time using cURL.

My example request looks like:

curl -X POST -d @file server:port

and I currently measure this using the time command in Linux:

time curl -X POST -d @file server:port

The time command only measures total time, though – which isn’t quite what I am looking for.

Is there any way to measure request and response times using cURL?

15 s
15

From this brilliant blog post… https://blog.josephscott.org/2011/10/14/timing-details-with-curl/

cURL supports formatted output for the details of the request (see the cURL manpage for details, under -w, –write-out <format>). For our purposes we’ll focus just on the timing details that are provided. Times below are in seconds.

  1. Create a new file, curl-format.txt, and paste in:

         time_namelookup:  %{time_namelookup}s\n
        time_connect:  %{time_connect}s\n
     time_appconnect:  %{time_appconnect}s\n
    time_pretransfer:  %{time_pretransfer}s\n
       time_redirect:  %{time_redirect}s\n
  time_starttransfer:  %{time_starttransfer}s\n
                     ----------\n
          time_total:  %{time_total}s\n

  2. Make a request:

     curl -w "@curl-format.txt" -o /dev/null -s "http://wordpress.com/"

    Or on Windows, it’s…

     curl -w "@curl-format.txt" -o NUL -s "http://wordpress.com/"

What this does:

-w "@curl-format.txt" tells cURL to use our format file
-o /dev/null redirects the output of the request to /dev/null
-s
tells cURL not to show a progress meter
"http://wordpress.com/" is
the URL we are requesting. Use quotes particularly if your URL has “&” query string parameters

And here is what you get back:

   time_namelookup:  0.001s
      time_connect:  0.037s
   time_appconnect:  0.000s
  time_pretransfer:  0.037s
     time_redirect:  0.000s
time_starttransfer:  0.092s
                   ----------
        time_total:  0.164s

I have not yet seen an option to output the results in microseconds, but if you’re aware of one, post in the comments below.

Make a Linux/Mac shortcut (alias)

alias curltime="curl -w \"@$HOME/.curl-format.txt\" -o /dev/null -s "

Then you can simply call…

curltime wordpress.org

Thanks to commenter Pete Doyle!

Make a Linux/Mac stand-alone script

This script does not require a separate .txt file to contain the formatting.

Create a new file, curltime, somewhere in your executable path, and paste in:

#!/bin/bash

curl -w @- -o /dev/null -s "$@" <<'EOF'
    time_namelookup:  %{time_namelookup}\n
       time_connect:  %{time_connect}\n
    time_appconnect:  %{time_appconnect}\n
   time_pretransfer:  %{time_pretransfer}\n
      time_redirect:  %{time_redirect}\n
 time_starttransfer:  %{time_starttransfer}\n
                    ----------\n
         time_total:  %{time_total}\n
EOF

Then call it the same way as the alias:

curltime wordpress.org

Make a Windows shortcut (aka BAT file)

Create a new text file called curltime.bat in the same folder as curl.exe and curl-format.txt, and paste in the following line:

curl -w "@%~dp0curl-format.txt" -o NUL -s %*

Then from the command line you can simply call:

curltime wordpress.org

(Make sure the folder is listed in your Windows PATH variable to be able to use the command from any folder.)

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