Currency Exchange · head-to-head
Czech National Bank vs Frankfurter
The Czech National Bank publishes its official daily fixing of the koruna against roughly 30 foreign currencies, sourced from interbank market quotes and released every working day around 14:30 CET (weekends and holidays carry over the last valid fixing). Beyond the legacy raw XML feed this entry links to, CNB also runs a modern JSON REST API with interactive Swagger documentation and date-parameterized historical queries — and, like the old feed, it requires no key or registration.
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.
| Czech National Bank | Frankfurter | |
|---|---|---|
| Authentication | None | None |
| Pricing | free | free |
| Formats | XML, JSON | JSON, CSV, NDJSON |
| CORS | unknown | yes |
| HTTPS | Yes | Yes |
Frankfurter supports CORS, while Czech National Bank doesn't — pick Frankfurter for direct browser calls.