Alert thresholds for transaction limits

Alert thresholds for transaction limits let you receive notifications when a card's remaining spending limit drops below a level you configure. They complement transaction limits by giving you advance warning so you can top up, adjust limits, or notify cardholders before transactions are declined.

Alert settings are configured per card through the Create a card API or Update a card API endpoints using the alert_settings object. For the full structure and fields of the alert_settings object and how to configure them, see Configure alert thresholds for transaction limits.

How alert thresholds work

When you set transaction limits on a card (for example, per transaction, daily, or monthly), the card has a remaining spend amount for each interval. That remaining amount decreases as authorizations and purchases are processed and increases when credits such as refunds or reversals are applied.

An alert threshold is a percentage you configure in the alert_settings.low_remaining_transaction_limit.percent field. When the card's remaining spending limit falls at or below that percentage of the limit, Airwallex sends a webhook event to your endpoint. You can then automate follow-up actions such as adding funds, increasing the limit via the API, or notifying the cardholder.

Relationship to transaction limits

Alert thresholds do not change how transaction limits are enforced. They only trigger notifications. Authorizations are still approved or declined based on the same transaction limits and remaining limits API logic. Configuring an alert threshold does not block or allow any transaction; it only determines when you receive the issuing.card.low_remaining_transaction_limit webhook event.

You set the threshold as a percentage so that you are notified while there is still remaining spend. For example, with percent set to 10, a webhook is sent once the remaining limit is at or below 10% of the limit for that interval, giving you time to act before the limit is fully used.

When alerts are useful

• Proactive funding: You receive a webhook when remaining limit is low and can add funds or adjust limits before the next transaction is attempted.
• Operational visibility: Your systems can log or surface low-limit cards for review without polling the Get card remaining limits API endpoint continuously.
• User experience: You can notify cardholders or support staff when a card is close to its limit so they can request an increase or top up in advance.

See also

• Transaction limits: How spending limits are set and applied on cards.
• Configure alert thresholds for transaction limits: Steps to set thresholds and receive webhook notifications.
• Listen for webhook events (Issuing): Issuing webhook event types, including issuing.card.low_remaining_transaction_limit.