I need to set up a daily batch job that makes an REST API call to an external service and updates contact records in salesforce. The data in the external service changes once daily. The external system stores the salesforce contact record ID which I hope to use to update records in salesforce.
My question is, the typical salesforce batch job has a "start" method where I am supposed to gather the records for processing. In this scenario, I do not know which records I will be processing as that is the point of my API call to the external service.
Is it possible to omit the start method or something similar that will still allow me to use the batch framework of salesforce?