Does gzipcheck.com detect the use of Apache mod_deflate for compression?

Yes, mod_deflate is detected, the test shows a result of "gzip compressed".

Does your gzip tool test secure pages that use https://

Yes! Although the original version of gzipcheck did not test certificate pages using https, the new version does.

Does your gzip tool test ftp resources?

No, the current version of our gzip test tool does not test ftp sites.

I entered localhost but it could not be tested?

Our tool cannot test your localhost since our server is not located on your network. This is similar to the W3C Validator limitation.

Does your gzip tool detect scripts that gzip files?

Yes, when you use any language to invoke compression and gzip files, our gzip check tool recognizes the encryption and reports "gzip compressed". Popular languages include ASP, Ruby, Python, Perl, Php, Java, and others.