If you rename (or symlink) the pandoc executable to
pandoc-server, or if you call pandoc with
server as the first argument, it will start up a web server
with a JSON API. This server exposes most of the conversion
functionality of pandoc. For full documentation, see the pandoc-server
man page.
If you rename (or symlink) the pandoc executable to
pandoc-server.cgi, it will function as a CGI program
exposing the same API as pandoc-server.
pandoc-server is designed to be maximally secure; it
uses Haskell’s type system to provide strong guarantees that no I/O will
be performed on the server during pandoc conversions.