Base Fiat Currency

Overview

Base Fiat Currency gives a merchant one consistent unit for financial reporting and operational comparison. A business may price products and maintain accounting in USD, EUR, or another fiat currency while accepting several cryptocurrencies through the same payment system.

It differs from Display Currency, which controls how prices appear to the payer, and from Quote Currency, which identifies the unit used for a particular exchange-rate quote. Those values can match the base currency, but they serve different purposes.

When an invoice is created, the requested amount can be denominated in a supported fiat currency and converted into a Pay Currency. The system should record the original fiat amount, rate source, quote timestamp, and resulting crypto amount for later reconciliation.

Changing the base currency affects reports, thresholds, and comparisons but should not rewrite historical transaction values. Existing payments need their original pricing currency and rate evidence. Accounting systems may additionally translate transactions under formal reporting rules.

Merchants operating across countries should avoid using one base currency as a substitute for local pricing or tax requirements. The base currency is an internal anchor, while customer presentation, settlement assets, and statutory reporting can use different units.

Data models should never overwrite the original transaction currency with the base currency. Each payment can carry original order amount, display amount, quoted crypto amount, paid crypto amount, and converted reporting value. Finance teams can then reproduce exchange gains, rounding differences, and revenue figures without pretending that the blockchain transfer occurred in the accounting currency.

The merchant should document who can change the base currency and which reports, thresholds, and dashboards depend on it. A controlled migration should preserve historical comparability.