howoldis
The most simple, but still useful, command line app. Done just because I was bored someday.
From the GitHub README:
~> go get github.com/fiatjaf/howoldis
~> howoldis github.com
github.com is available at least since May 2008, 10 years ago.
~> howoldis github.com/fiatjaf
github.com/fiatjaf is available at least since Jun 2015, 3 years ago.
howoldis fetches data from the Wayback Machine to quickly tell you how old a website is.