Recovering Failed Stablecoin Payment Webhooks Without Duplicate Credits
A customer has transferred funds, but their account balance has not changed. The cause may be an unreachable callback URL, a signature failure, or a processing timeout. Check the on-chain transaction, gateway order, and business credit separately.
Identify the failing stage
Query the gateway order first. Then inspect callback reachability, the HTTPS certificate, reverse proxy routing, and receiver logs. Distinguish requests that never arrived from rejected signatures, failed processing, and lost responses. Record order identifiers, timestamps, response codes, and outcomes without logging secrets.
Verify the original request body
UUGate callbacks use callbackSecret, which has a different purpose from the merchant API Key. Preserve the raw request body and follow the documented timestamp, nonce, and signature checks. Reformatting JSON before verification can change the signed content. Do not disable verification to clear a backlog.
Make crediting atomic
Use the merchant identity and gateway order number as a business uniqueness constraint. Update the order and credit the balance in one database transaction. An application-level “check, then credit” sequence alone cannot prevent two concurrent callbacks from crediting twice.
A collection address can receive multiple deposits, so it is not a suitable deduplication key. Callback processing and query recovery must share the same crediting logic.
Acknowledge durable work
For short processing, return the documented success response after committing the transaction. For asynchronous processing, verify the request and persist the event to a durable queue before acknowledging it. Monitor failed consumers and queue backlog. Acknowledging an event held only in memory risks losing it during a restart.
Recover missed updates with queries
After service recovery, query unfinished business orders and pass the result through the same business validation and idempotent crediting rules. Check the merchant, order, asset, network, and amount. A browser success page or customer screenshot is not sufficient evidence for crediting.
Before launch, test duplicate and concurrent callbacks, a lost response after crediting, restarts, and query recovery. Follow the API documentation for exact fields and statuses, review the payment API solution, and check plan limits.