You can run the Python script which translates Spanakopita Markup to HTML from the command line. There are no dependencies other than the Python standard library and it should be easy to use. Simply provide the Spanakopita markup as stdin and the HTML will be emitted on stdout.
The Spanakopita Plugin project also includes a standalone browser tool, but that is intended more for testing purposes. To use it, download the project and select the appropriate Target in Xcode.