GoAltdns is a permutation generation tool that can take a list of subdomains, permute them using a wordlist, insert indexes, numbers, dashes and increase your chance of finding that estoeric subdomain that no-one found during bug-bounty or pentest. It uses a number of techniques to accomplish this. It can allow for discovery of subdomains that conform to patterns. GoAltdns takes in words that could be present in subdomains under a domain (such as test, dev, staging) as well as takes in a list of subdomains that you know of. The tool itself is very simple and is built with golang concurrency providing it very quick execution times.