unrot.link is a hosted service for restoring old links. It's a simple service that takes a URL and returns a new URL that will check whether the URL is still up, and if not, redirect to the Internet Archive copy. If the URL is still available, it will quickly redirect to the target URL.
This repository can be used to either clone and create your own hosted instance (see self hosting docs), or so you can add your own domain to the pre-approved list of domains (see access approval docs).