BIS Effective Exchange Rates (Currency Strength) API
How strong each currency is on a trade-weighted basis, served live from the Bank for International Settlements' open statistics API — no key, nothing cached. An effective exchange rate (EER) measures a currency against a basket of its trading partners' currencies, not just one pair — it is the single best gauge of whether a currency is broadly strengthening or weakening. The BIS publishes nominal and real (inflation-adjusted) EER indices for 64 economies, against a broad (64-economy) or narrow (27-economy) basket, all on a base of 100. The rankings endpoint returns every economy's current EER index, ranked, so you can see the world's strongest and weakest currencies at a glance. The country endpoint returns one economy's EER index with its history and its 12-month change. The movers endpoint ranks the biggest currency gainers and losers over the past year — who has appreciated and who has depreciated most. Everything is the BIS's own compiled data, live, nothing stored; figures are monthly. This is the trade-weighted currency-strength layer for any forex, macro, trade or research app. Distinct from bilateral FX-rate and central-bank APIs — this is effective exchange rates: real and nominal trade-weighted currency strength, from the BIS. 3 endpoints, no key on our side.
api.oanor.com/eer-api