Connecting my WordPress store with an external billing system

Job ID: 36225991

Budget: $250 – $750 USD

I am looking for a professional PHP programmer to connect an external billing system with my WordPress store.
The external API is
https://aliphia.com/api-docs/
I just want to link product quantities so that if I add a quantity in the invoicing program, the number increases automatically in my WordPress store, and if the purchase is made from my WordPress store, the number decreases in the external billing system.
Related categories: PHP WordPress MySQL HTML Scripting