Amazon Finances v0 is switched off in 13 days — your migration checklist (and the reconciliation gaps no one warns you about)

On 28 August 2026, Amazon removes the Finances v0 API. If your reporting, accounting sync, or reconciliation still calls /finances/v0/..., it stops returning data the day it goes dark — and payouts stop tying out.

I run five Amazon Selling Partner API integrations in production, and Amazon's own developer team publicly validated a reconciliation method of mine in their official GitHub repo (issue #5353). Here's the migration, minus the fluff — plus the parts that quietly break.

The move: v0 → listTransactions

The replacement is listTransactions (Finances 2024-06-19). It gives you an earlier, itemized view of financial events without waiting for the settlement report. The field mapping is mostly mechanical — but three things trip almost everyone up.

The 3 reconciliation gaps

1. Fees with no order id. Not every financial line has an AmazonOrderId. Service fees, subscription charges and some adjustments reference only a FinancialEventGroupId (the payout group). If you reconcile purely at the order level, those lines silently vanish and your totals won't match the payout.

2. Group-level vs order-level. Reconcile at the payout/group total first, then drill into line items. Don't expect the transactions and the settlement flat-file to be 1:1 at the row level.

3. Settlement matching. Match settlement-id to the financial event group at the payout level. The relatedIdentifierName on each transaction (ORDER_ID or FINANCIAL_EVENT_GROUP_ID) is how you cross-reference — miss the group-only case and reconciliation drifts by a few cents you'll never find manually.

What to do this week (checklist)

• Grep your codebase for every finances/v0 call — know your exposure.
• Map each v0 field to its listTransactions equivalent.
• Handle the fee-with-no-order-id case explicitly.
• Add a reconciliation check: transactions grouped by payout must tie to the settlement total.
• Add retries + a log that surfaces every divergence (no silent syncs).
• Test against a real payout before 28 Aug — not a demo.

Free tools

• 30-second scanner — paste your integration; it flags every v0 call that breaks and shows the listTransactions replacement. Runs in your browser, nothing uploaded.
• Free field guide — the full v0 → listTransactions field map plus these edge cases.

Both, the migration kit, and the done-for-you option are here: https://proficientstack.com/sp-api.html

If the deadline is on your radar but not yet on anyone's desk, that page has the browser-side scanner — and if you'd rather just have it migrated and reconciled cleanly before the 28th, in writing, no calls, that's exactly what I do.

13 days. Better to find the gaps now than on the 29th.