Commerce abuse

How to reduce automated inventory hoarding

Protect reservations and stock holds by reviewing expiration, per-operation limits, and purchase completion instead of relying only on checkout challenges.

By the easycaptcha team · Published August 28, 2026

Inventory hoarding ties up limited stock or service capacity without completing the transaction. OWASP calls this denial of inventory. A flow can therefore be abused even when no payment reaches the processor.

Reservations and availability

Identify which operation removes availability: adding to a cart, starting checkout, reserving an appointment, or creating a temporary booking. The main payment button may be too late to protect that resource.

Put rules at the hold boundary

Review hold duration, release behavior, and how many simultaneous holds one permitted actor can create. Enforce rules on the server and include alternate APIs. A browser-only counter does not prevent direct reservation calls.

A challenge can add friction before a hold when your policy calls for it. It does not replace stock accounting, transaction state, or authorization. Keep the resource lifecycle explicit so a failed or abandoned flow releases inventory correctly.

Compare holds with completions

Measure started holds, expired holds, confirmed purchases, and availability over time. Investigate repeated abandoned patterns alongside normal behavior. Do not label every abandoned cart malicious; visitors also change their minds or encounter errors.

Use an evaluation that includes genuine customers on shared networks and people who need longer to finish a form. A very short hold can reduce abuse while also making the product unusable for legitimate visitors.

Test interruption paths

Exercise proof rejection, an application crash after a hold, a payment failure, and a delayed confirmation. Check that the server releases or confirms exactly the intended resource and that retries do not create multiple reservations.

A useful result is restored availability alongside genuine completion, not merely fewer checkout requests. Read payment-abuse prevention for the later payment boundary and rate controls for managing operation volume independently of a visible challenge.