4.10Upsert and idempotency

Here's why this matters enormously.

Suppose Mule receives:

CUST-10042

and successfully writes Salesforce.

Before Mule returns HTTP response:

network timeout

The caller assumes failure and retries.

With blind Create:

request #1
→ Account CUST-10042

request #2
→ another Account CUST-10042

Bad.

With Upsert:

request #1
→ insert CUST-10042

request #2
→ update CUST-10042

Much safer.

This is called:

Idempotency

Conceptually:

perform operation once
≈
perform same operation repeatedly

from the perspective of unwanted side effects.

Interview phrase:

“I try to design retryable integrations around stable external identifiers and upsert semantics where the business model allows it.”

That's a strong sentence.