Payment Match Window

Overview

What does Payment Match Window mean?

Payment Match Window is the permitted time interval within which an observed transaction may be matched to a specific payment request or obligation.

How it works in practice

A payment match window bounds which observations may be considered candidates for an invoice, based on time or block range. It reduces accidental assignment when addresses are reused or a customer pays after expiry. The system must define the relevant clock: invoice creation time, observed mempool time, block inclusion time and provider ingestion time can differ. A robust implementation records all of them where available and treats late-but-valid deposits through a separate exception policy rather than discarding on-chain evidence.

Limits and common misunderstandings

An overly narrow window misses legitimate delayed confirmations; an overly wide one increases collisions on shared addresses. Provider clock drift and chain reorganizations can change observations after an initial match.

Additional implementation considerations

Time-window logic requires an explicit event clock. A gateway seeing a mempool transfer at 11:59 may not receive block confirmation until 12:20; an invoice expiring at noon needs a policy that answers which timestamp matters. Persist both original observation and confirmation timestamps. Tests should cover provider outages, timezone conversions, chain reorganizations and a transaction that appears again under a different event delivery ID.

Related glossary terms

Payment After Expiration; Payment Match Rule; Early Crypto Payment