What is Fail-closed?
Fail-closed means that when something goes wrong — a payment can’t be verified or the platform is unreachable — access is denied rather than granted. Payrelayer’s SDKs return 502 instead of ever serving paid content for free.
Fail-closed is the safe default for a paywall: the worst case is a paying caller being told to retry, never an unpaid caller getting paid content. It’s the opposite of “fail-open,” which would leak value on errors.
Related terms