17.26Async design

Client
 ↓
POST /onboarding
 ↓
validate
 ↓
persist/publish command
 ↓
202 Accepted

Then:

Queue
 ↓
Onboarding worker
 ↓
Salesforce Upsert
 ↓
success

During outage:

message remains/retries

rather than every user request failing immediately.