[voidlogic]

It doesn't say, but probably none. My guess would be they just used "net/http" + Gorilla (maybe). Gorilla: http://www.gorillatoolkit.org/

[elithrar]

Given it sounds like this application is not "web facing" (i.e. not an API nor rendering HTML), the use of any "web framework" or Gorilla doesn't make much sense.

[voidlogic]

I write back-end stuff like this all the time and it often has admin interfaces.