9.15What belongs where?
A useful decision table:
| Concern | Layer |
|---|---|
| Salesforce SOQL | System API |
| Salesforce field mappings | System API |
| Salesforce connector auth | System API |
| Combine Salesforce + Billing | Process API |
| Business eligibility rules | Process API |
| Mobile-specific response | Experience API |
| Partner-specific field names | Experience API |
This distinction is worth memorizing.