1) With REST API call to my ERP system I can get XML data with actual inventory quantity in "warehouse". Each item also contains given SKU code.
2) What would be best ways to make an app for updating inventory amounts both "on-demand","once-per-day" to corresponding SKU number? Should I learn, for example, Insomnia API client + GraphQL or Node.js + React or there is simpler solution to "map" an API call from ERP to Shopify.
Thanx in advance!
So this can actually be created using a Zapier flow, if your CRM is a Zapier partner that can integrate with shopify: https://zapier.com/apps/shopify/integrations
If that fails, you can always resort back to https://ifttt.com/ for easier walkarounds.
But, and that's the crucial part here - if your API does not integrate with any of these platforms, you'd need to create a background job on your server that goes to your ERP system, polls that information, and then updates it in the store.
Let me know which one is of more interest to you, and I can assist in all three fronts. Also - does your ERP has an externally available REST API endpoint, or is it local to your network? If it's local than this becomes a bit tougher (though still doable).
Zenaton (https://zenaton.com) can be a great way to synchronise your data between Shopify and your ERP. On a regular basis. There is no limit on what you can do as it's code-based. Happy to help if you need to. Best