How does multi-currency work in Magento?

Magento supports multiple currencies natively. We typically wire it up like this: (1) Allowed currencies set per website. (2) Live FX feed (ECB, OpenExchangeRates, fixer.io) with cron import every hour. (3) Per-currency rounding rules and price-display formatting per locale. (4) Optional fixed prices in customer-group + website scope to avoid FX drift on premium SKUs. Customers see only the currency for their region; admins see all currencies side-by-side in reports.