Github: sectorsect/manyheads
Blog: manyheads introduction

manyheads is a multi-threaded utility for making many HEAD requests. It can also do GET (or whatever method you want)!

manyheads was written to collect request data for a list of a few thousand subdomains. It is not built for stealth, but it will collect request data for a list of thousands of webpages in a short time.

manyheads will output in greppable and JSON formats, as well as sending each request result to a new file.

It’s quick, it’s dirty, but it got the job done and you can too.