I want to create an external API web service to manage the inventory of my physical point of sale, I want to use barcodes. What I would like to know is what is the appropriate route to do this using the shopify server side and the databases, what language should I use.
I'd recommend using the GraphQL API to manage inventory - there's a range of different queries and mutations for getting info on inventory, and changing inventory, like the inventoryAdjustQuantities mutation. It's also possible to use this API to set barcodes on each product variant. You can use a front-end framework like React alongside node.js to build your app.