Invoice Price Lock

Overview

Understand the idea

A merchant can lock a USD product price for the lifetime of a checkout while still recalculating the BTC amount until the customer selects BTC. Alternatively, it can lock the crypto amount itself for a short payment window.

Price lock differs from exchange-rate lock when taxes, fees, inventory, or product discounts can still change the final amount. The complete calculation context should be frozen.

A lock can expose the merchant or provider to market movement. Hedging, short lifetimes, spreads, and amount limits are common risk controls.

Risks include unclear lock scope, stale inventory, manipulated client countdowns, late payment, partial payment, and customer disputes over revised invoices.

Systems should preserve locked value, currency or asset, calculation version, start, expiry, quote source, eligibility, payment attempt, and repricing decision.

Controls around Invoice Price Lock should prevent silent mutation after issue. For Invoice Price Lock, corrections should use a revision, credit note, replacement, or auditable adjustment with explicit links to the original. For Invoice Price Lock, reconciliation should prove how every payment, fee, refund, write-off, and conversion changed the outstanding balance and which document version the customer actually received.

What actually happens

An invoice price lock fixes an exchange-rate quote or crypto amount for a defined period so customers know what to send. Without a lock, the same $100 invoice could require changing amounts of BTC as market prices move. The lock establishes an agreed calculation window; it does not stop market prices from changing in the outside world.

A merchant's pricing backend determines fiat amount, allowed asset, rate source, spread if any, precision and a server-side expiry. Checkout presents the resulting token quantity and instructions. During the valid period, matching should compare the observed token amount against the locked expectation and explicit tolerance rules. After expiry, a revised quote receives a new version; earlier quotes and payments remain in history for reconciliation. Whoever bears exchange-rate exposure must be specified in the provider's settlement rules.

Decisions and failure cases

A price lock is not a hedge unless a party actually assumes or offsets market risk. Delayed inclusion, token transfer fees, network costs and late payments can still create mismatches. Preserve the original quote, timestamps, rounding and rate source so both sides can understand the outcome.

Related concepts

Price Lock, Invoice, Invoice Rate Lock.

Further reading

OxaPay technical documentation.