# Rate Zap

> Free, fast, multilingual currency converter for US Dollar (USD), Japanese Yen (JPY) and Chinese Yuan (CNY). Enter any amount and see the converted value in all three currencies at once, using live exchange rates refreshed daily.

Rate Zap has no sign-up, no ads, no tracking beyond a single self-hosted analytics script, and works without JavaScript. Exchange rates are sourced from the Open Exchange Rates API (open.er-api.com) with US Dollar as the base currency.

## Languages

- [English](https://ratezap.fanshikun.com/?lang=en): Default interface.
- [中文 (Simplified Chinese)](https://ratezap.fanshikun.com/?lang=zh)
- [日本語 (Japanese)](https://ratezap.fanshikun.com/?lang=ja)

## Conversion examples

- [Convert 100 USD](https://ratezap.fanshikun.com/?currency=USD&amount=100)
- [Convert 10000 JPY](https://ratezap.fanshikun.com/?currency=JPY&amount=10000)
- [Convert 100 CNY](https://ratezap.fanshikun.com/?currency=CNY&amount=100)

## Pair pages (SEO landing)

- [USD to JPY](https://ratezap.fanshikun.com/usd-to-jpy): USD → JPY
- [USD to CNY](https://ratezap.fanshikun.com/usd-to-cny): USD → CNY
- [JPY to USD](https://ratezap.fanshikun.com/jpy-to-usd): JPY → USD
- [JPY to CNY](https://ratezap.fanshikun.com/jpy-to-cny): JPY → CNY
- [CNY to USD](https://ratezap.fanshikun.com/cny-to-usd): CNY → USD
- [CNY to JPY](https://ratezap.fanshikun.com/cny-to-jpy): CNY → JPY

## Machine-readable resources

- [sitemap.xml](https://ratezap.fanshikun.com/sitemap.xml): Per-language URLs with hreflang alternates.
- [robots.txt](https://ratezap.fanshikun.com/robots.txt): Crawl policy (AI crawlers explicitly allowed).
- [/health](https://ratezap.fanshikun.com/health): JSON status of the exchange-rate cache.

## API

JSON endpoints for programmatic access. No API key required.

- GET /api/convert?from=USD&amount=100 — core feature: returns ALL three currencies (CNY, JPY, USD) at once. Omit 'to' to see every currency simultaneously.
- GET /api/convert?from=USD&to=JPY&amount=100 — single-pair conversion. Returns { from, to, amount, result, rate, lastUpdate }.
- GET /api/rates — list current rates for all supported currencies.

## FAQ

- **What does Rate Zap do?** Converts a single amount between USD, JPY and CNY simultaneously using live daily exchange rates.
- **Is it free?** Yes — no sign-up, no payment.
- **Where do the rates come from?** Open Exchange Rates API (open.er-api.com), USD-based, refreshed daily.
- **Are the rates suitable for actual trading?** No — for reference only; use your bank's rate for real transactions.