The direct answer is to run a sandbox exercise in which the invoice automation is deliberately treated as unavailable, a trained operator follows the manual procedure, and a second person reconciles the result before automation resumes. The test must prove both continuity and transaction integrity: customers receive the right invoice once, accounting records remain traceable, and queued automated work cannot later create a duplicate.
Define the failure and the safe scope
Choose one realistic scenario, such as a no-code connector outage, failed accounting export, unavailable payment provider, or broken approval rule. Use test customers and test products unless the business has an approved, tightly controlled production exercise. State which steps are unavailable and which systems remain authoritative.
NIST describes contingency planning as a coordinated strategy for recovering systems, operations, and data after disruption, including short-term manual processing where appropriate. Its contingency-planning guidance recognizes alternate manual processing as one way to maintain affected business processes.
Write the manual procedure at transaction level
The procedure should name the operator, approver, source records, numbering rule, tax and discount checks, delivery method, payment instructions, accounting entry, evidence retained, and escalation path. Include a manual-run identifier on every test invoice and in the reconciliation log. Never invent invoice numbers outside the accounting system's controlled sequence.
Specify the stop condition for automation. Pause the trigger or isolate the test customer before manual creation, and capture the queue or pending-job state. If the workflow cannot be paused safely, the fallback is not ready because the same source event may later be processed automatically.
Exercise creation and delivery in a sandbox
Create three cases: an ordinary invoice, a corrected invoice, and a failed or delayed payment. Stripe's invoicing test guide recommends testing common scenarios before launch and explains that a sandbox is isolated from the live integration. It supports creating test invoices, observing webhook events, simulating payment failures, and testing manual bank-transfer invoices.
Verify the source customer, line items, quantities, dates, currency, tax treatment, payment terms, and contact address. Require the approver to compare the generated document with the source record. Send only through the test environment or to an owner-controlled mailbox. Record timestamps and identifiers without copying payment credentials into the test notes.
Prove reconciliation and restart safety
Have a second person compare the manual invoice register with the accounting system, payment provider, customer communication, and paused automation queue. Each source transaction should map to exactly one invoice and one current status. Correct discrepancies through documented credit, void, or amendment processes instead of deleting evidence.
Before resuming automation, mark the manually handled source items so the worker will not process them again. Restart with one low-risk item, observe logs and events, and confirm the queue skips or recognizes completed manual transactions. Then release the remaining queue in controlled batches.
Test recovery, not just paperwork
NIST SP 800-34's contingency planning guide includes alternate manual processing and a validation plan with expected results, actual results, success status, and performer. Use that structure for the exercise. Measure time to pause automation, create and approve an invoice, reconcile it, resume service, and close exceptions.
Record every unclear instruction, unavailable credential, missing role, numbering conflict, and duplicate risk. Assign corrective actions and repeat the failed portion after the procedure is updated. A tabletop discussion is useful preparation, but it does not prove that staff can operate the real screens, find the source data, or reconcile the restart.
Passing criteria
The fallback passes only if authorized staff can complete the essential workflow within the stated time, all test invoices are accurate and traceable, no live customer is contacted, no duplicate is produced after restart, and every exception has an owner. Review the procedure after system, staff, tax, payment, or approval changes.
A manual fallback is not an improvised spreadsheet. It is a controlled alternate process with clear authority, transaction evidence, duplicate prevention, and a tested path back to automation.
Sources
- Contingency planning — National Institute of Standards and Technology
- Test Stripe Invoicing — Stripe
- SP 800-34 Rev. 1, Contingency Planning Guide for Federal Information Systems — National Institute of Standards and Technology, May 1, 2010