Payment Callback

Overview

Meaning in plain language

A payment callback is a server-to-server notification sent to a configured endpoint when a payment’s status or related information changes. Payment Callback must specify the producer, consumer, event type and version, delivery URL, stable event identifier, signature method, timestamp, retry policy, and expected response.

How it works

Receivers should use HTTPS, verify the documented authentication or signature, validate the schema, deduplicate atomically, and persist before acknowledging. Delivery can be duplicated, delayed, reordered, or abandoned after retry limits. When amounts, currency, or status are uncertain, query the provider and reconcile authoritative records. They allow backend systems to react after the customer has left the checkout page.

For Payment Callback, metrics should separate transport success from business success. Payment Callback is a provider notification or invocation concerning payment state; the exact event contract and security requirements must be stated rather than inferred from the word callback. Returning an HTTP success before durable storage risks losing an event if later processing fails.

A Payment Callback handler should acknowledge only after durable receipt when the provider's retry contract depends on the response.

Monitoring for Payment Callback should track delivery age, signature failures, duplicate rate, retry exhaustion, and unresolved business events.

Where people get it wrong

Callbacks may be delivered several times or arrive late. Use event IDs and idempotent updates, and fall back to authoritative status lookup when callback delivery is uncertain.

Related concepts

Payment Statistics API, Payment Endpoint, Webhook.