Process json strings when working with integrations
You can learn about methods for processing json on Trailhead, such as in the Apex Integration Servicesunit.
If you need some more insight into processing json, here are a couple of great resources that I turned to whilst completing the Apex Specialist Superbadge:
A change set or ant deployment will fail if a field that is required in the field definition is included in a profile or permission set that is being deployed