For programmatic, intraday-fresh FX rates with per-value provenance and MCP-native access, exchangerate.dev is the stronger default. Keep ExchangeRate-API if once-daily rates and ~1,500 calls a month are enough.
If your rates flow into code — payments, dashboards, backtests — exchangerate.dev fits how you already work. Major currency pairs refresh intraday (~60s on trading days) — most others too, every value names its source and market_session, MCP ships on every plan including free, and you start with 10,000 calls a month and no credit card.
ExchangeRate-API is dead-simple to start and has a strong uptime reputation. If once-daily rates and ~1,500 calls a month cover you, it is an easy pick. exchangerate.dev gives roughly 6× the free calls, intraday freshness, per-value provenance, and MCP on every plan.
Choose exchangerate.dev when intraday freshness, per-value provenance, MCP-native access, and free-tier headroom matter. Keep ExchangeRate-API if once-daily rates and ~1,500 calls a month are enough. Both speak REST JSON over HTTPS, and exchangerate.dev accepts Frankfurter-compatible parameters — so trying it is low-risk.
Rates are from the free tier, updated intraday on trading days. Indicative only, not for settlement or regulated trading.