I have external REST service with some info about products. This comes from some software of the company.
How I can use this JSON I got to create nodes and fill in the fields in nodes?
Also, I need to detect when something is changed and to update field in existing node.
I'm on Drupal 8 and I'm getting JSON with POST method (I need to send 'id' parameter in order to get product for exact client).
The Feeds Module does this great for D7, offering cron imports and ability to update existing nodes/etc. Looks like they have a D8 branch, but I haven't tested. Might be helpful to look at for you.