Exchange rates

The exchange rates API exposes fiat currency pairs for pricing, valuation, and reconciliation workflows. Call the routes under /api/v2 for all new integrations: they return DALP response envelopes and use the shared collection query format for lists.

The routes cover reads only. Feed setup, feed governance, and legal valuation policy remain outside this API contract.

Endpoints

Exchange rate routes use ISO 4217 alpha-3 currency codes. Use uppercase codes such as EUR and USD in path parameters and filters.

List available rates

Call the list endpoint before you request a specific conversion path. It returns one record per currency pair after DALP deduplicates the active feed rows for each pair. When several active feeds describe the same pair, DALP keeps the most recently observed feed; see feed selection for the full rule.

curl --globoff "https://your-platform.example.com/api/v2/exchange-rates?filter[baseCurrency]=EUR&filter[quoteCurrency]=USD&page[limit]=50&page[offset]=0&sort=-effectiveAt" \
  -H "X-Api-Key: sm_dalp_xxxxxxxxxxxxxxxx"

The response uses the collection envelope:

{
  "data": [
    {
      "baseCurrency": "EUR",
      "quoteCurrency": "USD",
      "rate": 1.08,
      "effectiveAt": "2026-03-22T10:30:00.000Z",
      "updatedAt": "2026-03-22T10:31:00.000Z",
      "feedAddress": "0xabcdef1234567890abcdef1234567890abcdef12"
    }
  ],
  "meta": {
    "total": 1,
    "facets": {
      "baseCurrency": [{ "value": "EUR", "count": 1 }],
      "quoteCurrency": [{ "value": "USD", "count": 1 }]
    }
  },
  "links": {
    "self": "/v2/exchange-rates?filter[baseCurrency]=EUR&filter[quoteCurrency]=USD&page[limit]=50&page[offset]=0&sort=-effectiveAt",
    "first": "/v2/exchange-rates?filter[baseCurrency]=EUR&filter[quoteCurrency]=USD&page[limit]=50&page[offset]=0&sort=-effectiveAt",
    "next": null,
    "prev": null,
    "last": "/v2/exchange-rates?filter[baseCurrency]=EUR&filter[quoteCurrency]=USD&page[limit]=50&page[offset]=0&sort=-effectiveAt"
  }
}

rate, effectiveAt, updatedAt, and feedAddress can be null when a listed pair exists but has no usable observation yet. Treat a listed pair as discoverable; do not assume it is fresh enough for a valuation workflow.

Read one current rate

Call the pair read endpoint when you already know the pair you need. DALP responds with 404 and EXCHANGE_RATE_NOT_FOUND when no current rate exists for the requested pair; the endpoint never returns null for a missing rate. When baseCurrency and quoteCurrency are the same code, DALP gives an identity rate of 1.

curl "https://your-platform.example.com/api/v2/exchange-rates/EUR/USD" \
  -H "X-Api-Key: sm_dalp_xxxxxxxxxxxxxxxx"

The response carries one data object and a self link:

{
  "data": {
    "baseCurrency": "EUR",
    "quoteCurrency": "USD",
    "rate": 1.08,
    "effectiveAt": "2026-03-22T10:30:00.000Z"
  },
  "links": {
    "self": "/v2/exchange-rates/EUR/USD"
  }
}

Feed selection

DALP keeps one rate per currency pair. When more than one active feed describes the same pair, DALP resolves a single record using these rules:

• A feed that has produced an observation outranks a feed with no observations yet.
• Among feeds with observations, the most recently observed rate wins, and that choice is stable: the same set of active feeds resolves to the same rate on every call.

Once a pair has at least one observed feed, the list and read endpoints agree on the resolved rate. A pair with overlapping observed feeds always returns one consistent rate, never a different feed on each request. Use feedAddress on a list record to confirm which feed produced the rate you read. Before any feed for a pair has been observed, the two endpoints differ: the list endpoint surfaces the pair as a discoverable record with a null rate, while the read endpoint returns 404 with EXCHANGE_RATE_NOT_FOUND. Treat a freshly registered pair as discoverable until its first observation lands.

Inverse-pair resolution on a read

The single-pair read at GET /api/v2/exchange-rates/{baseCurrency}/{quoteCurrency} also resolves the reverse pair when the requested direction has no observed feed:

• If an observed feed exists for the requested pair, DALP returns its rate directly.
• If the requested pair has no observed feed but the reverse pair does, DALP inverts the reverse-pair rate and serves that value.
• If neither direction has an observed feed, DALP responds with 404 and EXCHANGE_RATE_NOT_FOUND.

A read can therefore return a usable rate for EUR/USD even when only a USD/EUR feed is observed, by inverting that reverse rate. The list route preserves feed direction: it returns each pair exactly as its feed describes it. To confirm whether a rate came from a direct or inverted feed, compare the read result against the corresponding list record.

Read historical rates

Call the history route when you need a time-bounded record of observations for reconciliation, reporting, or a valuation review.

curl --globoff "https://your-platform.example.com/api/v2/exchange-rates/EUR/USD/history?filter[effectiveAt][gte]=2026-03-01T00:00:00.000Z&filter[effectiveAt][lte]=2026-03-31T23:59:59.999Z&page[limit]=100&sort=-effectiveAt" \
  -H "X-Api-Key: sm_dalp_xxxxxxxxxxxxxxxx"

The history response uses the same collection envelope as the list endpoint:

{
  "data": [
    {
      "baseCurrency": "EUR",
      "quoteCurrency": "USD",
      "rate": "1.08",
      "effectiveAt": "2026-03-22T10:30:00.000Z"
    }
  ],
  "meta": {
    "total": 1,
    "facets": {}
  },
  "links": {
    "self": "/v2/exchange-rates/EUR/USD/history?filter[effectiveAt][gte]=2026-03-01T00:00:00.000Z&filter[effectiveAt][lte]=2026-03-31T23:59:59.999Z&page[limit]=100&sort=-effectiveAt",
    "first": "/v2/exchange-rates/EUR/USD/history?filter[effectiveAt][gte]=2026-03-01T00:00:00.000Z&filter[effectiveAt][lte]=2026-03-31T23:59:59.999Z&page[limit]=100&page[offset]=0&sort=-effectiveAt",
    "next": null,
    "prev": null,
    "last": "/v2/exchange-rates/EUR/USD/history?filter[effectiveAt][gte]=2026-03-01T00:00:00.000Z&filter[effectiveAt][lte]=2026-03-31T23:59:59.999Z&page[limit]=100&page[offset]=0&sort=-effectiveAt"
  }
}

Historical rate values are decimal strings. Use decimal arithmetic instead of converting them through binary floating-point numbers in financial workflows.

List supported currencies

Call the supported-currencies endpoint before you render a target-currency picker. It returns the ISO 4217 alpha-3 codes currently present in the configured rate-source snapshot.

curl "https://your-platform.example.com/api/v2/exchange-rates/supported-currencies" \
  -H "X-Api-Key: sm_dalp_xxxxxxxxxxxxxxxx"

{
  "data": {
    "providerKey": "open-er-api",
    "currencies": ["AED", "EUR", "USD"]
  },
  "links": {
    "self": "/v2/exchange-rates/supported-currencies"
  }
}

providerKey identifies the configured exchange-rate source snapshot. Treat currencies as the allowed picker set for the next exchange-rate refresh cycle.

Parameters and fields

Related pages

• Token price resolution explains how token pricing can use base-price and FX feeds for converted token prices.
• Operational integration patterns covers retries, readback checks, and reconciliation patterns around API integrations.
• API reference remains the contract source for generated clients and route details.