FDE Interview Questions: Order-to-Cash Sync
Examine common interview follow-up questions about an order-to-cash integration design. Evaluate timeouts during record creation, recovery from partially completed operations, return processing, and reconciliation failures that record counts alone may not reveal. Identify who is responsible for resolving reconciliation mismatches and explain release approval decisions to finance and sales stakeholders.
We'll cover the following...
- Handling timeouts during order creation
- Why message deduplication and an order upsert are not enough
- When SO-920 exists: Resuming only unfinished work
- How six shipped and two returned change recovery
- What must reconcile when counts match and INV-301 is paid
- Who owns the mismatch and what permits release
- Practice: Defending H-552 without destination idempotency
- FDE role-specific questions
Harborline durably records the approved order creation intent for OPP-410. Attempt A1 sends the request to NetSuite, but the response is lost. Another notification for the same order creation request arrives with a different delivery ID, but the integration has not confirmed the NetSuite order ID.
Handling timeouts during order creation
Mark A1 as outcome-unknown because NetSuite may have created the order, but the integration has no confirmation. Retain operation ID harborline:sf-prod:OPP-410:create-order:1 and the fingerprint of its approved request payload.
Assigning a new create-operation key to the second notification would treat the same business request as a separate order creation. This can create two accepted orders, even if each notification is processed only once. Salesforce's integration guidance identifies duplicate records and repeated transactions as retry risks. It recommends unique identifiers and duplicate checks when creating records in external systems.
Determine what evidence is required to confirm the existing NetSuite order or safely retry the creation request.
Recover or hold?
OPP-410’s approved create intent is committed with identity harborline:sf-prod:OPP-410:create-order:1 and a fixed payload fingerprint. A1 times out after submission; D2 arrives with a different delivery ID. One possibly stale search returns no order.
Consider two deployments:
- Verified: Destination protection atomically binds this identity to the approved payload and resulting order, including concurrent submissions, throughout recovery. Changed payloads cannot silently reuse it. Reliable lookup resolves the identity to an accepted order or documented in-progress outcome.
- Unverified: Those guarantees are absent and search may lag.
Which recovery plan is safe?
In both deployments, give D2 a fresh create key; its different delivery ID makes it a separate create.
Verified: recover under the same identity and fingerprint using reliable lookup; verify and record the accepted order or respect in-progress status. Unverified: hold creation and assign investigation.
In both deployments, retry creation immediately with the original identity; the empty search establishes that A1 created nothing.
Hold creation in both deployments; even verified atomic protection and reliable lookup cannot support automatic recovery after a timeout.
The decisive difference is whether destination guarantees cover the crash window between remote creation and local confirmation. A retry queue cannot close that window by itself. For Harborline’s conditional safe branch, require verified destination guarantees:
Atomic duplicate protection binds the scoped operation identity to its approved payload and resulting order, including concurrent submissions.
Reliable lookup resolves that identity to the accepted order or a documented in-progress outcome.
Protection remains valid throughout the recovery window; changed payloads cannot silently reuse the identity.
Treat these as deployment conditions, not established NetSuite features. In the verified branch, A2 records SO-920 after resolving and verifying the same operation identity.
If lookup is inconclusive or protection is unavailable, hold creation and assign ...