Payments
Decline code
A decline code is the reason an issuing bank gives for refusing a card authorization, and it determines whether retrying that card could ever succeed.
The operationally important split is soft versus hard. Insufficient funds is soft — a timing problem where the same card will likely work in a few days. Stolen card, lost card and closed account are hard: no retry will ever succeed on that credential.
Retrying hard declines is worse than not retrying. It recovers nothing and raises your overall decline rate, which can in turn affect authorization rates on legitimate charges. Route hard declines directly to a payment-method update request instead.
In depth: How to reduce involuntary churn