Create exchange rate (NOT IMPLEMENTED)
NOTICE: Multi-currency support is NOT implemented in Arcus.
This endpoint accepts writes for forward-compatibility but exchange rate data has no business
effect on any transaction. Returns HTTP 501 unless entities.settings.multi_currency_enabled
is true (which no entity has set, as of 2026-05-22).
Append-only per-day FX snapshots.
Currency fields accept either a UUID (from the currencies resource) or an ISO-4217 code
(e.g. “USD”, “EUR”, “GBP”). Codes are resolved to UUIDs at write time; UUIDs are canonical
in the database (Rule 23 SSOT). If both from_currency and from_currency_id are provided,
from_currency_id takes precedence.
effective_date is accepted as an alias for as_of_date.
Authorizations
API key issued per entity via Settings > Developers > API Keys.
Each key carries scopes (e.g. orders:read, products:write).
Bearer token format: Authorization: Bearer ark_live_ent_
Test keys use ark_test_ent_. Both are issued per entity
via Settings > Developers > API Keys.
Headers
Body
Exchange rate (units of to_currency per 1 unit of from_currency)
ISO-4217 currency code OR UUID of the source currency. Alias: resolved to from_currency_id.
^[A-Z]{3}$"USD"
UUID of the source currency (canonical form). Overrides from_currency if both provided.
ISO-4217 currency code OR UUID of the target currency. Alias: resolved to to_currency_id.
^[A-Z]{3}$"GBP"
UUID of the target currency (canonical form). Overrides to_currency if both provided.
Date this rate applies to. Alias: effective_date.
Alias for as_of_date. Accepted if as_of_date is not provided.
Rate source identifier (e.g. ecb
Response
Created exchange rate
The response is of type object.

