Fixer API

Currency Exchange / API Key Intermediate HTTP
Varies by plan (check documentation)

Overview

Fixer is a widely-used currency exchange and conversion API providing real-time, intraday, and historical exchange rates for 170+ currencies. A free API key is required; the free plan supports EUR as the base currency and up to 100 monthly requests via HTTPS. Fixer is popular for e-commerce, fintech dashboards, and international pricing features.

💡

Beginner Tip

Sign up at fixer.io to get your free API key. The free plan uses HTTP only (not HTTPS) and locks the base currency to EUR. Pass your key as a query parameter: ?access_key=YOUR_KEY.

Available Data

exchange rate between currencies
conversion result
supported currency list
historical rates

Example Response

JSON Response
{
  "base": "USD",
  "date": "2025-01-15",
  "rates": {
    "EUR": 0.92,
    "GBP": 0.79,
    "JPY": 149.5,
    "CAD": 1.35
  }
}

Field Reference

base The base currency for the rates (EUR on the free plan).
date The date of the exchange rate data.
rates Exchange rates for each currency code relative to the base currency.
timestamp Unix timestamp of the latest rates update.
success True if the request was processed without errors.

Implementation Example

const url = "https://fixer.io/";
// Replace headers or query params with the values required by this API.
const response = await fetch(url, {
  headers: {
  "X-API-Key": "YOUR_API_KEY"
  }
});
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data);

What Can You Build?

Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.

Common Errors & Troubleshooting

HTTPS not supported on free plan The free tier of Fixer restricts API access to HTTP only
Use http:// not https:// for the API base URL on the free plan. To use HTTPS you need a paid subscription.
Base currency cannot be changed The free plan fixes the base currency to EUR
Convert to your target base mathematically using the EUR rates, or upgrade to a paid plan to set any base currency.
401 Unauthorized API key is missing, invalid, or not yet activated
Ensure you are passing ?access_key=YOUR_KEY and that your account is verified on fixer.io.

Matrix Score Breakdown

🌐 Reachability 30/30
⚡ Speed 5/20
🔒 Security 5/15
🛠 Developer XP 12/20
✓ Reliability 10/15

Partially tested on Apr 5, 2026

Technical Specifications

Auth API Key
HTTPS NO
CORS UNKNOWN
Difficulty Intermediate
Verified: 2026-04-04

Alternatives to Fixer

Technical alternatives for different use cases.

Includes crypto rates alongside fiat currencies

Better For

Apps needing both fiat and crypto exchange rates

Trade-off

Enterprise SLA and guaranteed uptime

Same data provider with USD as base (vs EUR for Fixer)

Better For

USD-denominated applications

Trade-off

EUR-based financial applications

Simpler API with ECB rates, free tier available

Better For

Basic currency conversion on a budget

Trade-off

Historical rates and time-series data

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