Originally published on waveleta.com.
When developers ask me about FX data for the Waveleta Developer API, the first question is usually "does it update tick by tick?". The honest answer is no: Waveleta provides daily FX reference rates, refreshed each business day. For a surprising number of projects, that's exactly what you want. Here's the difference, and how to tell which one you need.
What is an FX reference rate?
A reference rate is a single, official-style exchange rate for a currency pair, published once per business day. It's a snapshot that everyone can point to: "the EUR/USD rate on 6 October was X".
Reference rates are:
- Stable: one value per pair per business day, so everyone using it gets the same number.
- Easy to cite: you can say exactly which date a rate is from.
- Informational: they're for information, reporting and conversion, not for live pricing.
What is an intraday quote?
An intraday quote changes throughout the day, often many times per second. It reflects the current market price at a given venue. Intraday data is what you need if the exact minute matters.
Which one do you need?
| Your project | Reference rates | Intraday |
|---|---|---|
| Currency converter on a blog or shop | ✅ Ideal | Overkill |
| Invoices, expenses, accounting | ✅ Ideal (date-stamped) | Not needed |
| Monthly or weekly reports | ✅ Ideal | Not needed |
| "Rate of the day" widget | ✅ Ideal | Not needed |
| Travel budget apps | ✅ Good fit | Not needed |
| Anything that depends on minute-by-minute prices | ❌ Not suitable | Needed |
If your users would be happy with "today's rate", reference rates are simpler, cheaper to serve and easier to explain.
Why daily rates are easier to build on
- Cache all day. The rate only changes once per business day, so you can cache aggressively. With the Waveleta API at €0.002 per call, a converter that refreshes FX twice a day costs about €0.12 a month.
- No confusing flicker. Users don't see a number change while they're reading it.
-
Clear dating. Each rate comes with the date it applies to (
as_of_datein the Waveleta API), so you can show "rate as of 6 Oct". - Weekends and holidays are predictable. No new rate is published on non-business days. Show the latest available date and you're done.
How FX works in the Waveleta API
GET /v1/fx/rates returns the current daily reference rate for each supported pair, with the pair, base and quote currencies, the rate and its date. FX is in early access in Waveleta, and the data is daily reference rates only, refreshed each business day. There's no intraday FX.
curl -s -H "Authorization: Bearer $WAVELETA_API_KEY" \
"https://api.waveleta.com/v1/fx/rates?limit=20"
Full Python and JavaScript examples are in the Waveleta API quickstart. On WordPress, the Waveleta WordPress plugin has a ready-made FX table and currency converter: see the Waveleta WordPress guide.
Pricing is prepaid: €20 minimum top-up, then €0.002 per call. Sign up here.
FAQ
Are Waveleta FX rates intraday?
No. They're daily reference rates, refreshed each business day.
What happens at weekends?
No new reference rate is published on non-business days. The API returns the most recent available rate and its date.
Can I use reference rates for a currency converter?
Yes. That's one of the best uses for them. Show the date next to the result.
Can I use them as live market prices?
No. Reference rates are for information, reporting and conversion only.
Informational only, not financial advice. Waveleta is not a broker.
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