My AI Agent Charged a Customer Twice in 11 Seconds

Описание и применение

Повторная обработка вебхука платежа привела к двойному списанию средств. Решение: сделать обработчик идемпотентным, используя уникальный ID события, сохранять его до выполнения действий и игнорировать повторные события.

Задача

Duplicate payment charges were created because the webhook handler did not dedupe repeated events, leading to a customer being charged twice.

Результат

Prevented double charges by making the webhook handler idempotent; added duplicate‑event tests and nightly reconciliation to catch similar issues early.

Рабочий процесс

• Receive payment.succeeded webhook
• Extract event_id from payload
• Check if event_id already processed in durable store
• If processed, return success and skip
• If not, record event_id
• Charge customer
• Provision account
• Send receipt email
• Return success

Доказательства

The provider had sent the payment.succeeded event three times.

Источник

The fix is small enough to be almost insulting, which is the point.

Источник