FX Rate API / Documentation

API Documentation

Base URL: https://www.sentisignal.com/api/v1/fx

Authentication

The public /currencies endpoint is open. Rate endpoints require an API key. Pass it via Authorization: Bearer YOUR_API_KEY or x-api-key.

curl -H "Authorization: Bearer YOUR_API_KEY" 
  https://www.sentisignal.com/api/v1/fx/rate?base=USD&quote=EUR

GET /currencies

Returns the tracked currency catalog. No authentication required.

curl https://www.sentisignal.com/api/v1/fx/currencies

GET /rate

Fetch the latest FX rate for a currency pair.

Parameters

Name	Type	Default	Description
`base`	string	required	3-letter base currency code
`quote`	string	required	3-letter quote currency code

Example

curl -H "Authorization: Bearer YOUR_API_KEY" 
  "https://www.sentisignal.com/api/v1/fx/rate?base=GBP&quote=PLN"

Response

{
  "status": "success",
  "timestamp": "2026-03-11T12:00:00Z",
  "data": {
    "base": "GBP",
    "quote": "PLN",
    "rate": 5.000000,
    "rate_date": "2026-03-11",
    "source": "ECB (European Central Bank)"
  },
  "meta": { "credits_used": 1, "plan": "free" }
}

GET /rate/historical

Fetch historical FX rates for a date range. Paid plans only. Responses include summary stats.

Parameters

Name	Type	Default	Description
`base`	string	required	Base currency
`quote`	string	required	Quote currency
`start_date`	string	required	Start date in YYYY-MM-DD
`end_date`	string	required	End date in YYYY-MM-DD
`interval`	string	daily	daily, weekly, monthly, yearly

Error Codes

Code	Message	Description
400	Invalid parameters	Malformed or missing pair/date parameters
401	Invalid API key	Missing, invalid, expired, or revoked API key
403	Plan restriction	Historical access is not available on the current plan
429	Rate limit exceeded	Per-minute or monthly request limit reached
500	Server error	Internal processing error or unavailable upstream data