Open Exchange Rates and XE are both REST FX rate APIs. The real differences are free-tier size, update frequency, and where each one starts charging — the table below has the specifics.
Open Exchange Rates's free tier: Up to 1,000 requests/month, hourly updates, base currency restricted to USD. XE's free tier: No permanent free tier — a free trial only. Check both against your expected monthly call volume before committing — a restricted base currency or a low monthly cap can force an upgrade sooner than the sticker price suggests.
Open Exchange Rates updates hourly on Free/Developer; every 30 minutes on Enterprise ($47/mo); every 5 minutes on Unlimited ($97/mo). XE updates daily on Lite; hourly on Intermediate; every 15 minutes on Prime. Live (minutely) rates are a $400–$1,500/year add-on, or bundled only on custom-priced Enterprise. Open Exchange Rates sources data from aggregated published sources (banks, financial data providers, and others), per Open Exchange Rates' own documentation. XE sources data from xE's own aggregated market data, per XE's published tier documentation.
Once the free tier runs out, Open Exchange Rates's cheapest paid plan is developer plan, $12/month, for 10,000 requests/month with hourly updates and all base currencies. XE's cheapest paid plan is lite plan, $799/year (annual billing only), for 10,000 requests/month with daily-only rates.
Open Exchange Rates: Up to 1,000 requests/month, hourly updates, base currency restricted to USD. XE: No permanent free tier — a free trial only.
Open Exchange Rates updates hourly on Free/Developer; every 30 minutes on Enterprise ($47/mo); every 5 minutes on Unlimited ($97/mo). XE updates daily on Lite; hourly on Intermediate; every 15 minutes on Prime. Live (minutely) rates are a $400–$1,500/year add-on, or bundled only on custom-priced Enterprise. Compare the specific plan you'd actually pay for, not just the headline tier — both vendors gate faster updates behind higher plans.
Neither currently does. No MCP integration is listed on Open Exchange Rates' pricing or signup pages. No MCP integration is listed on XE's Currency Data API documentation.
Open Exchange Rates's cheapest paid plan is developer plan, $12/month, for 10,000 requests/month with hourly updates and all base currencies. XE's cheapest paid plan is lite plan, $799/year (annual billing only), for 10,000 requests/month with daily-only rates. Compare against your actual monthly call volume, not just the sticker price — overage and rate-limit behavior varies by plan.
If you're choosing between Open Exchange Rates and XE mainly on free-tier size or update frequency, exchangerate.dev is worth a look too: a free tier of 10,000 calls/month across 465 pairs, no credit card required, major pairs updating roughly every 60 seconds on trading days, a source and market_session field on every response, and an MCP stdio bridge on every plan including free — a capability neither Open Exchange Rates nor XE currently lists.
Rates are from the free tier, updated intraday on trading days. Indicative only, not for settlement or regulated trading.