I really like the clean API docs, well done! Did you build it on your own or is that some REST doc framework? The only thing I was missing from the API (maybe those are there but left out in the docs, which would be totally fine) are links between your resources (to make it a bit more actual REST). You already more promimently documented the usecase ("create an invoice") instead of listing URL endpoints, but with lin…
The docs are an awesome repo by TripIt ( https://github.com/tripit/slate ). They aren't perfect, but they get you pretty far pretty quickly. Not sure what you mean by "links between your resources." Have an example? May be there (or we can build it if not). Correct on Unix time. Just being extra redundant.
[1] http://roy.gbiv.com/untangled/2008/rest-apis-must-be-hyperte...
[2] http://stateless.co/hal_specification.html