CurrencyFreaks vs Frankfurter

CurrencyFreaks delivers minute-level exchange rates for a notably broad basket — 166 fiat currencies plus metals and roughly 850+ cryptocurrencies, over 1,000 instruments in total — with both JSON and XML output and historical data reaching back to 1984. Its paid tiers unlock faster refresh intervals, a time-series endpoint, a fluctuation endpoint, and even an IP-to-currency lookup, positioning it as a more data-dense alternative to typical fiat-only rate APIs.

Frankfurter aggregates and republishes daily reference rates from roughly 84 central banks, not solely the ECB, covering 200+ currencies with history back to 1948, and supports current, dated, and time-series conversion queries, including filtering to a specific source institution. It's free with no API key and no request quotas beyond abuse-prevention rate limiting, returns JSON by default plus CSV and streaming NDJSON, and now also ships an official self-hosting Docker image and an MCP server for AI-agent integration. The project's site and docs moved from frankfurter.app to frankfurter.dev, with the old domain now redirecting.