Can you, please, provide a couple of quick API usage examples?

I’m really interested into trying to automate importing some of my existing notes into SN, but don’t actually understand how to use the API. Can you, please, provide a couple of quick entry-level API usage examples?

For example: how can I use SN API and Javascript to create a card with specified Title and Body at specified location?
Or how can I use SN API and Javascript to find if specific card exists?

Thanks in advance. If there are some general openAPI usage examples available online - please, point me there!
(BTW: maybe this is a good place to try to use SN cards to share the knowledge?)

OK, I see: this type of API uses https-requests (with curl).
I was even able to get the content of a specified card… :cowboy_hat_face:
Everything looks good so far.