Overview

This tool is designed to allow you to measure and display the 'Time To First Byte' (ttfb) for a given url. It can also help identify bottlenecks or latency issues that might be causing slow responses.

We also provide a python package if you prefer that to a bash script.

Usage

``` Usage: ./ttfb.sh [ -hfmv ] [ -c count ] [ -u url ]

-h    : Print this screen
-v    : show the current version of the script
-f    : Show full set of timing values
-m    : Show minimal setof timing values
-c    : How many times to test
-u    : The url to test

``` NOTE -u is not required if you put the url as the last parameter.

Results Output

Single Connection Test

Standard Output (Default)

─────────────────────────────────────────────────────────────────────────────────────────────────────────── Time to First Byte Test ─────────────────────────────────────────────────────────────────────────────────────────────────────────── Lookup Time: 0.005087 Connect Time: 0.025123 StartXfer Time (TTFB): 0.111106 Total Time: 0.111173 ───────────────────────────────────────────────────────────────────────────────────────────────────────────

Minimal Output (-m)

────────────────────────────────────────────────────────── Time to First Byte Test ────────────────────────────────────────────────────────── StartXfer Time (TTFB): 0.106124 Total Time: 0.106208 ──────────────────────────────────────────────────────────

Full Output (-f)

────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Time to First Byte Test ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Lookup Time: 0.004987 Connect Time: 0.022486 AppCon Time: 0.089366 PreXfer Time: 0.089427 Redirect Time: 0.000000 StartXfer Time (TTFB): 0.108404 Total Time: 0.108475 ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

Repeated Connection Test

It is also possible to specify how many connections to make when testing by adding the -c flag. This can be combined with the existing output flags (-m and -f)

─────────────────────────────────────────────────────────────────────────────────────────────────────────── Time to First Byte Test ─────────────────────────────────────────────────────────────────────────────────────────────────────────── Lookup Time: 0.005112 Connect Time: 0.034810 StartXfer Time (TTFB): 0.119705 Total Time: 0.119777 Lookup Time: 0.005087 Connect Time: 0.023240 StartXfer Time (TTFB): 0.108551 Total Time: 0.108623 Lookup Time: 0.004158 Connect Time: 0.021478 StartXfer Time (TTFB): 0.110971 Total Time: 0.111036 Lookup Time: 0.005108 Connect Time: 0.022807 StartXfer Time (TTFB): 0.111455 Total Time: 0.111526 Lookup Time: 0.004764 Connect Time: 0.022720 StartXfer Time (TTFB): 0.111475 Total Time: 0.111547 ───────────────────────────────────────────────────────────────────────────────────────────────────────────

Exceptional lag test

─────────────────────────────────────────────────────────────────────────────────────────────────────────── Time to First Byte Test ─────────────────────────────────────────────────────────────────────────────────────────────────────────── Lookup Time: 0.005257 Connect Time: 0.023145 StartXfer Time (TTFB): 0.123785 Total Time: 1.399076 Lookup Time: 0.004230 Connect Time: 0.021909 StartXfer Time (TTFB): 0.109505 Total Time: 1.218776 Lookup Time: 0.004481 Connect Time: 0.022189 StartXfer Time (TTFB): 0.111843 Total Time: 1.293919 Lookup Time: 0.005262 Connect Time: 0.023195 StartXfer Time (TTFB): 0.113860 Total Time: 1.258916 Lookup Time: 0.005240 Connect Time: 0.023303 StartXfer Time (TTFB): 0.113752 Total Time: 1.227184 ───────────────────────────────────────────────────────────────────────────────────────────────────────────

NOTE: We used https://flash.siwalik.in/ which is a website which allows you to intentionally add lag/latency to a connection. We forced the addition of 1000ms just to demonstrate the script functions as expected.

In the above example prefixed the normal url with https://flash.siwalik.in/delay/1000/url/ to create this intentional lag.

Timing Key

| Time | Description | | --- | --- | | Lookup time (timenamelookup) | The time, in seconds, it took from the start until the name resolving was completed. | | Connect time (timeconnect) | The time, in seconds, it took from the start until the TCP connect to the remote host was completed. | | AppCon time (timeappconnect) | The time, in seconds, it took from the start until the SSL/SSH/etc connect/handshake to the remote host was completed. | | PreXfer time (timepretransfer) | The time, in seconds, it took from the start until the file transfer was just about to begin. This includes all 'pre-transfer' commands and negotiations that are specific to the particular protocol(s) involved. | | Redirect time (timeredirect) | The time, in seconds, it took for all redirection steps include name lookup, connect, pretransfer and transfer before the final transaction was started. 'timeredirect' shows the complete execution time for multiple redirections. | | StartXfer time (timestarttransfer) | The time, in seconds, it took from the start until the first byte was just about to be transferred. This includes 'timepretransfer' and also the time the server needed to calculate the result. | | Total time | The sum of all the other times |

Response Times: The 3 Important Limits

Short note for your information.

• 0.1 second – is about the limit for having the user feel that the system is reacting instantaneously, meaning that no special feedback is necessary except to display the result;
• 1.0 second – is about the limit for the user’s flow of thought to stay uninterrupted, even though the user will notice the delay. Normally, no special feedback is necessary during delays of more than 0.1 but less than 1.0 second, but the user does lose the feeling of operating directly on the data;
• 10 seconds – is about the limit for keeping the user’s attention focused on the dialogue. For longer delays, users will want to perform other tasks while waiting for the computer to finish, so they should be given feedback indicating when the computer expects to be done. Feedback during the delay is especially important if the response time is