Fixed Rate Provider

Use FixedExchangeRateProvider when accounting has approved a specific rate and its evidence outside the package. The provider is deterministic and makes no network request.

import { FixedExchangeRateProvider, createEfatura } from '@akira-io/efatura';

const provider = new FixedExchangeRateProvider({
  sourceCurrency: 'EUR',
  targetCurrency: 'CVE',
  rate: 110.265,
  effectiveAt: new Date('2026-07-21T00:00:00.000Z'),
  retrievedAt: new Date('2026-07-21T10:00:00.000Z'),
  rateType: 'custom',
  provider: 'Rate approved by the accounting team',
  sourceUrl: 'https://internal.example/rates/2026-07-21',
});

const efatura = createEfatura(config, { exchangeRateProvider: provider });
const prepared = await efatura.prepareInvoiceToCve(invoiceInEur, {
  sourceCurrency: 'EUR',
  rateType: 'custom',
});

The configured currency pair and rate type must match the preparation request. The requested effective date cannot precede the configured quote date. provider and sourceUrl must identify the evidence that accounting approved.

The complete EUR-to-CVE example provides a runnable invoice, builds the DFE XML, renders the DFA, and verifies the original EUR payable amount without network access.

See Currency Conversion for constructor fields, validation rules, precision, and audit persistence.