Support and examples for REST API

Hello there Generals!

I'm writing here after few hours of searching for some reliable materials about OpenCart v3 REST API. I need some examples at least, maybe list of available methods I can call, and some description of required/optional parameters. Any official and working documentation would be needed.

I've tried examples from https://opencart-api.com/tutorial/ but they doesn't seem to work, and I'm not sure if they are for v3 since there is no place to enter API key and API Username there.

To be more specific: I need to write a script which will import products to opencart. My first thought (since I wanted to make some kind of integration with 3rd party software) was to use this API, although I cannot find any materials in official docs about it.

And since I'm new to OpenCart - maybe this API is fully compatible with OpenCart v2??