Overview

Amazon has introduced a new TRANSACTION_UPDATE webhook that fires instantly whenever a payment is captured on any order, no matter which marketplace the seller operates in. The real‑time push gives sellers immediate visibility into cash flow and lets them trigger downstream processes without waiting for periodic reports. Because the alert arrives before the order appears in the standard Order API feed, sellers can begin processing while the order data is still being synchronized.

Key Points

• Universal coverage — The notification is emitted for every marketplace a seller is enrolled in, from the United States and Canada to Germany, Japan, and Brazil, ensuring a single integration handles all global sales.
• Near‑instant delivery — Amazon pushes the payload to the registered endpoint within a few seconds of the transaction being posted, typically under three seconds in live environments.
• Consistent payload schema — Each message carries the Amazon order identifier, transaction type (such as charge, refund, or fee), monetary amount, currency code, and an ISO‑8601 timestamp, mirroring the structure used by other SP‑API event types.
• Idempotent processing — A unique transactionId field accompanies every alert, allowing sellers to safely deduplicate retries without losing any financial events.
• Explicit subscription — Sellers must add TRANSACTION_UPDATE to their notification list via the SP‑API’s createSubscription endpoint or through the Seller Central UI before any alerts are sent.
• Sandbox testing support — Amazon provides a dedicated sandbox endpoint that reproduces live‑like transaction events, enabling developers to validate webhook handling before going production.
• Retry policy — If the seller’s endpoint fails to return a 200 OK within five seconds, Amazon automatically retries using exponential back‑off up to six attempts, guaranteeing delivery reliability.
• Security compliance — Every POST includes standard SP‑API authentication headers and a SHA‑256 signature, so sellers can verify the source before processing the data.