Wayback Machine for Chrome, Firefox, Safari, and Android is an extension that allows you to access numerous archived web pages quickly.

It has happened to us all at one time or another; you go to your favorite page or link, and they are gone. Wayback Machine vast amounts of pages within its archives and allows you to go back to a previous date and retrieve data. There are millions of sites with their associated data (images, source code, documents, etc.) that are conveniently saved in this database.

Wayback Machine is perfect for seeing what a past version of a website looked like, and it will permit you to grab the source code from any site that may not be readily available for whatever reason. You can also gain access to websites that are no longer in existence. It can also perform automated detection of 404, 408, 410, 451, 500, 502, 503, 504, 509, 520, 521, 523, 524, 525, and 526 error codes and check to see if there are archived versions of the URLs available.