7.48A realistic Salesforce error strategy

Suppose:

POST /customers

We might classify:

API validation error
    ↓
400

Salesforce business validation failure
    ↓
422 or domain-specific response

Salesforce connectivity
    ↓
retry
    ↓
if exhausted → 503

Salesforce authentication/config issue
    ↓
don't keep retrying indefinitely
    ↓
500/503 + operational alert

unexpected DataWeave/runtime bug
    ↓
500

The exact HTTP choices depend on your contract.

The important thing is classification.