Similar to the network tab in Google Chrome or Mozilla Firefox, this crate helps you find the timings for:

• DNS lookup (if domain is specified, i.e. no IP is given)
• TCP connection start
• TLS handshake (if https/TLS is used)
• Initial GET-Request
• TTFB (Time To First Byte)

It builds upon the crates trust-dns-resolver for modern and secure DNS resolving of domains and native-tls for handling TLS v1.2/1.3.

CLI + lib work on Linux, MacOS, and Windows.

Install with cargo install ttfb. It takes one argument and passes it to the library. The string you pass here as first argument is the same as for the library function.

Additionally, the CLI takes a -k/--insecure option.
Example: $ ttfb -k https://expired.badssl.com

The library exposes the function ttfb(url: String). The string can be for example:

• phip1611.de (defaults to http://)
• http://phip1611.de
• https://phip1611.de
• https://phip1611.de?foo=bar
• https://sub.domain.phip1611.de?foo=bar
• http://12.34.56.78/foobar
• https://1.1.1.1
• 12.34.56.78/foobar (defaults to http://)
• 12.34.56.78 (defaults to http://)

If you installed the CLI and invoke it like $ ttfb https://phip1611.de, the output will look like:

TTFB for https://phip1611.de (by [email protected])
PROPERTY        REL TIME (ms)   ABS TIME (ms)
DNS Lookup    :         0.755           0.755  (probably cached)
TCP connect   :        35.484          36.239
TLS Handshake :        36.363          72.603
HTTP GET Req  :         0.011          72.614
HTTP Resp TTFB:        76.432         149.046

This crate uses the Rust edition 2021. This means, the MSRV is 1.56.1 stable.