Use this service when you need this capability: returns the latest daily ECB EUR foreign-exchange reference rate, not a real-time quote. ECB source data is free; the price covers SignalHarness normalization and delivery. Every result identifies the observation date, source, and freshness.
0.005 USDC per call
x402 V2 exact payment on Base mainnet (eip155:8453) using USDC. The HTTP 402 challenge confirms the exact requirements before an authorized payment.
POST https://signalharness.ai/api/agent/services/fx_rate/invokeReturns the latest daily ECB EUR foreign-exchange reference rate, not a real-time quote. ECB source data is free; the price covers SignalHarness normalization and delivery. Every result identifies the observation date, source, and freshness.
Daily ECB reference data, not real-time quotes. ECB source data is free; the service price covers normalization and delivery. Check the observation date, attribution, and freshness warnings in each result.
| Field | Type | Required | Limits |
|---|---|---|---|
| base | string | Required | Allowed: EUR; Minimum length 3; Maximum length 3 |
| quote | string | Required | Pattern: ^[A-Z]{3}$; Minimum length 3; Maximum length 3 |
{
"base": "EUR",
"quote": "USD"
}{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"additionalProperties": false,
"minProperties": 2,
"maxProperties": 2,
"required": [
"base",
"quote"
],
"properties": {
"base": {
"type": "string",
"enum": [
"EUR"
],
"minLength": 3,
"maxLength": 3
},
"quote": {
"type": "string",
"pattern": "^[A-Z]{3}$",
"minLength": 3,
"maxLength": 3
}
}
}Illustrative output from the canonical adapter fixture and schema. It is not a completed paid execution or a current live observation.
{
"base": "USD",
"quote": "USD",
"symbol": "EUR/USD",
"rate": 1e-8,
"asOf": "2026-09-12",
"retrievedAt": "example0000000000000",
"source": {
"provider": "example",
"dataset": "example",
"sourceUrl": "https://example.com/resource",
"freeAccessUrl": "https://example.com/resource",
"retrievedAt": "example0000000000000",
"attribution": "example",
"notice": "example"
},
"warnings": [
"Verify the caller-supplied data before relying on this result."
]
}{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"additionalProperties": false,
"minProperties": 8,
"maxProperties": 8,
"required": [
"base",
"quote",
"symbol",
"rate",
"asOf",
"retrievedAt",
"source",
"warnings"
],
"properties": {
"base": {
"type": "string",
"pattern": "^[A-Z]{3}$",
"minLength": 3,
"maxLength": 3
},
"quote": {
"type": "string",
"pattern": "^[A-Z]{3}$",
"minLength": 3,
"maxLength": 3
},
"symbol": {
"type": "string",
"pattern": "^[A-Z]{3}/[A-Z]{3}$",
"minLength": 7,
"maxLength": 7
},
"rate": {
"type": "number",
"minimum": 1e-8,
"maximum": 1000000000
},
"asOf": {
"type": "string",
"pattern": "^\\d{4}-\\d{2}-\\d{2}$",
"minLength": 10,
"maxLength": 10
},
"retrievedAt": {
"type": "string",
"minLength": 20,
"maxLength": 32
},
"source": {
"type": "object",
"additionalProperties": false,
"minProperties": 7,
"maxProperties": 7,
"required": [
"provider",
"dataset",
"sourceUrl",
"freeAccessUrl",
"retrievedAt",
"attribution",
"notice"
],
"properties": {
"provider": {
"type": "string",
"minLength": 1,
"maxLength": 128
},
"dataset": {
"type": "string",
"minLength": 1,
"maxLength": 256
},
"sourceUrl": {
"type": "string",
"pattern": "^https://",
"minLength": 9,
"maxLength": 2048
},
"freeAccessUrl": {
"type": "string",
"pattern": "^https://",
"minLength": 9,
"maxLength": 2048
},
"retrievedAt": {
"type": "string",
"minLength": 20,
"maxLength": 32
},
"attribution": {
"type": "string",
"minLength": 1,
"maxLength": 256
},
"notice": {
"type": "string",
"minLength": 1,
"maxLength": 512
}
}
},
"warnings": {
"type": "array",
"minItems": 0,
"maxItems": 8,
"items": {
"type": "string",
"minLength": 1,
"maxLength": 128
}
}
}
}Timeout: 12000 ms. Full schemas are in OpenAPI.
This schema-valid request returns the canonical HTTP 402 challenge without executing the service. A payment-capable client validates the challenge, signs only with prior authority and budget, and retries the identical body.
curl -i -X POST https://signalharness.ai/api/agent/services/fx_rate/invoke \
-H "Content-Type: application/json" \
--data '{"base":"EUR","quote":"USD"}'