Retry logic is the rule set behind a payment retry: the instructions a merchant, billing platform or processor follows to decide whether a failed payment should be attempted again, how long to wait and what to change on the next attempt. The main entry explains retries in general. Retry logic refers specifically to the decision rules.
In card acquiring the starting point is the decline code returned by the issuer. Soft declines, such as insufficient funds or a temporary issuer fault, may succeed later and are worth retrying. Hard declines, such as a closed account or a stolen card, will not, and card network rules prohibit resubmitting them and cap the number of attempts allowed in a set period, with fees for excessive retries. Good logic also chooses timing, for example retrying near a typical payday, and may send the next attempt through a different acquirer, a technique known as cascading.
For subscriptions, retry logic works alongside dunning messages to reduce involuntary churn. The same phrase is used in software engineering for repeating a failed network call, which is a related but separate matter handled with backoff delays and idempotency keys.