Indexer is a file explorer program, similar to Windows Explorer or OSX Finder, but for a web server, instead of a computer. Indexer also includes several features besides simply listing files in a directory, such as previewing many different file types, providing a convenient QR code to easily get to the same file on your phone that you are viewing on your computer, allowing the server admin to lock certain folders from view, providing a clean mobile interface, allowing people to securely upload files in to a public directory, and most importantly, being highly customizable.