Currencylayer

Overview

Currencylayer (an APILayer product) provides real-time and historical exchange rates for 168 currencies. Auth is a free API key — like other APILayer APIs, invalid keys return HTTP 200 with "success": false (verified).

Quick Start

Live rates (replace YOUR_KEY):

curl "http://api.currencylayer.com/live?access_key=YOUR_KEY&currencies=USD,CNY"

{
  "success": true,
  "timestamp": 1724300000,
  "source": "USD",
  "quotes": { "USDUSD": 1, "USDCNY": 7.2 }
}

Historical:

curl "http://api.currencylayer.com/historical?access_key=YOUR_KEY&date=2024-01-01"

Convert:

curl "http://api.currencylayer.com/convert?access_key=YOUR_KEY&from=USD&to=CNY&amount=100"

Authentication

• Register at currencylayer.com → free API key (emailed).
• Send it as the access_key query parameter.
• Invalid keys return 200 + "success": false (verified) — check the JSON.

Rate Limits & Notes

• Free tier: 100 requests/month (USD source only) — small; paid plans scale.
• Free tier source is USD; currencies= trims the response.
• The API is served over http (https is paid on some tiers) — use https when available.
• Historical and conversion endpoints are on paid tiers (free tier is live only).

FAQ

Is Currencylayer free? Free tier: 100 requests/month; more is paid.

Why 200 with success:false? APILayer convention — check the success field in the response body.

What’s the free source currency? USD.