I created this site to allow anyone to quickly and easily assess the security of their HTTP response headers. It has been free, and always will be, so that anyone who wants to use it can do and that's really important to me. I want the security and information that securityheaders.io offers to be available to as many people as possible.
Unfortunately though, developing and hosting such a site isn't free and I've been happily paying the costs out of my own pocket so far. In order to continue providing the service free to anyone who wishes to use it, I'm now offering sposnorship to cover some of the costs.