1 Best APIs for Any Base Currency (paid) in Nigeria

Open Exchange Rates is one of the most widely deployed foreign exchange rate APIs in the world, used by thousands of applications ranging from e-commerce platforms and accounting software to fintech apps and content management systems. The service provides clean, reliable JSON exchange rate data for over 200 currencies, with rates updated hourly on the free tier and in real time on paid plans. Historical data going back to 2001 is available for all supported currencies, making it one of the deepest historical forex datasets accessible through a simple API. For Nigerian developers building currency-aware applications, Open Exchange Rates provides dependable NGN rate data alongside every other major world currency. Nigeria's currency situation makes exchange rate data critically important for application developers. The Nigerian Naira (NGN) has experienced significant depreciation against the US Dollar and other hard currencies over the past decade, driven by oil price volatility, foreign exchange policy changes, and structural economic factors. Nigerian applications that deal with foreign currencies — e-commerce platforms, accounting tools, remittance services, salary calculation apps for multinational employees, and investment platforms — all need accurate, regularly updated exchange rate data to function correctly. The /latest.json endpoint is the most commonly used endpoint, returning current exchange rates for all 200+ currencies from the specified base currency. On the free plan, only USD is available as the base currency — meaning all rates are expressed as units of currency per 1 USD. The USD/NGN rate is available on the free plan. For Nigerian applications that need NGN as the base currency (showing how much USD, EUR, or GBP costs in naira terms), the Starter plan ($12/month) enables any base currency. For most Nigerian applications, the USD-base approach with client-side inversion is functionally equivalent. Historical rates are available via /historical/{YYYY-MM-DD}.json, returning exchange rates as they were on any past date. This capability is essential for Nigerian accounting software and ERP systems that need to record foreign currency transactions at the exchange rate on the transaction date — a requirement under International Financial Reporting Standards (IFRS) and a common requirement in Nigerian corporate accounting practice. With rates available back to 2001, Nigerian finance teams can reconstruct historical exchange rate data for any period their records cover. The /convert endpoint performs currency conversion: specify an amount, a from-currency, and a to-currency, and receive the converted amount at the current rate. For Nigerian e-commerce platforms that display product prices in multiple currencies, this endpoint handles the arithmetic server-side without the developer needing to fetch rates and calculate manually. The /time-series endpoint returns exchange rate data over a date range, ideal for building trend charts and calculating average rates over periods. A Nigerian corporate treasurer tracking the average USD/NGN rate over each quarter, or a Nigerian researcher analyzing the correlation between naira depreciation and inflation, can use time-series data directly without downloading and processing historical files. Open Exchange Rates also provides OHLCV (open, high, low, close, volume) daily rate data for currency pairs — useful for Nigerian forex analytics tools that need to display candlestick charts or calculate volatility metrics for currency pairs. The free plan provides 1,000 API requests per month with hourly rate updates — sufficient for a low-traffic application or prototype. The Starter plan ($12/month) provides 10,000 requests per month, unlocks any base currency, and removes the USD-only restriction. The Production plan ($97/month) provides real-time rate updates and 100,000 requests per month, appropriate for high-traffic Nigerian fintech applications. All plans use a simple app_id API key parameter with no request signing, making integration extremely quick.