Best Free Currency Exchange API in 2026 — No API Key Required
If you need exchange rate data for your application, your options range from free-with-caveats to expensive-with-everything. Most developers start by searching "free currency API" and end up with a service that caps at 100 requests per month, requires a credit card for signup, or returns stale data cached from yesterday. This article compares the major free currency exchange APIs available in 2026 and helps you find the best fit for your project.
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The Landscape of Free Currency APIs in 2026
Before we dive into individual APIs, here is the honest comparison of what is available. We evaluated each API on five criteria: whether it requires an API key, the number of supported currencies, update frequency, the free tier limits, and CORS support for browser usage.
| API | API Key | Currencies | Updates | Free Limit | CORS |
|---|---|---|---|---|---|
| Currency Exchange Tool ⭐ | No | 100+ | Live | Unlimited | ✅ |
| Frankfurter | No | ~30 (ECB) | Daily | Unlimited | ✅ |
| MoneyConvert | No | 182+ | 5 min | Rate-limited | ❌ |
| ExchangeRate-API (Open) | No | 160+ | Daily | Rate-limited | ✅ |
| ExchangeRate-API (Free) | Yes | 160+ | Daily | 1,500/mo | ✅ |
| FreeCurrencyAPI | Yes | 32 | Daily | 1,000/mo | ✅ |
| Open Exchange Rates | Yes | 170+ | Hourly | 1,000/mo | ✅ |
| AllRatesToday | Yes | 160+ | 60 sec | Limited | ✅ |
| Fixer.io | Yes | 170+ | Daily | 100/mo | ✅ |
| CurrencyAPI.net | Yes | 300+ | Daily | 500/mo | ✅ |
Key takeaway: Only a handful of APIs work without requiring any API key or signup. Among those, most either limit you to ECB-only currencies (~30 pairs) or impose aggressive rate limiting. Currency Exchange Tool stands out as the only completely open API with 100+ currencies, live rates, and no hard monthly limit.
1. Currency Exchange Tool (currencyexchangetool.com)
Best for: Developers who want instant, friction-free access to live exchange rates without signing up for yet another service.
This is the API behind the currencyexchangetool.com converter. It is completely open — no API key, no signup, no monthly cap. It supports 92 currencies on the V1 API and 25 pre-configured pairs on legacy endpoints. Rates are fetched live from Yahoo Finance on each request, so you always get the current market rate.
Example — Python
import requests
res = requests.get(
'https://www.currencyexchangetool.com/api/convert',
params={'amount': 100, 'from': 'USD', 'to': 'EUR'}
)
data = res.json()
print(f"100 USD = {data['result']} EUR")Example — JavaScript
const res = await fetch(
'https://www.currencyexchangetool.com/api/convert?amount=100&from=USD&to=EUR'
);
const data = await res.json();
console.log(`100 USD = ${data.result} EUR`);| Feature | Details |
|---|---|
| API Key Required | No — completely open |
| Signup Required | No |
| Currencies | 92 (V1) / 25 (legacy) |
| Update Frequency | Live (per request) |
| Free Limit | Unlimited (fair use) |
| Historical Data | Up to 365 days |
| CORS | ✅ Enabled on V1 |
| XML Output | ✅ Google Sheets compatible |
| SSL/HTTPS | ✅ |
2. Frankfurter
Best for: Projects that only need major currency pairs sourced from the European Central Bank.
Frankfurter is an open-source currency API that sources rates from the ECB. It is completely free and requires no API key. The v2 API (released in 2025) supports 201 currencies back to 1948, NDJSON streaming, and CSV output. It also offers an MCP server for AI assistants. Frankfurter is self-hostable if you need full control.
Trade-offs: Only ~30 freely floating currencies are available via the ECB source. Rates update once per day (~16:00 CET). There is no currency conversion endpoint — you fetch rates and calculate the conversion yourself.
3. ExchangeRate-API
Best for: Projects that need broad currency coverage and can tolerate an API key.
ExchangeRate-API has been around since 2010 and offers three tiers: an open (no-key) endpoint that is rate-limited and requires attribution, a free API key tier with 1,500 requests per month, and a paid Pro plan at $10/month for 30k requests. The free tier covers 160+ currencies with daily updates.
Trade-offs: The open endpoint is aggressively rate-limited. The free API key tier requires signup and still caps at 1,500 requests per month. Historical data is not available on the free tier.
4. Open Exchange Rates
Best for: Applications that need hourly updates and are okay with a free tier of 1,000 requests/month.
Open Exchange Rates is another well-known provider. Their free plan offers 1,000 requests per month, hourly updates, and 170+ currencies. They also provide a 10-year historical data archive. The free plan is limited to USD base currency only.
Trade-offs: Requires credit card for signup (even for the free plan). USD base only on the free tier. Low monthly request cap for production use.
5. MoneyConvert (moneyconvert.net)
Best for: Quick access to 182+ currencies without registration.
MoneyConvert offers a free JSON API for 182+ currencies updated every 5 minutes. No authentication is required. Their endpoint returns a single JSON object with all rates relative to USD.
Trade-offs: Rate limiting is not transparent. USD base only. No CORS headers — cannot be used directly from the browser. No dedicated documentation page with code examples.
How to Choose the Right API for Your Project
Here is a quick decision guide based on your needs:
- Side projects / hackathons: Currency Exchange Tool or Frankfurter — zero setup friction.
- Production fintech app: Currency Exchange Tool (V1) for CORS + structured error handling, or ExchangeRate-API Pro for SLAs.
- AI assistant integration: Frankfurter (MCP server) or Currency Exchange Tool (simple REST).
- Google Sheets automation: Currency Exchange Tool (XML output) or ExchangeRate-API (IMPORTXML compatible).
- Historical analysis: Frankfurter (back to 1948) or Open Exchange Rates (10-year archive).
- Crypto + fiat: UniRateAPI (593 currencies including 420+ crypto).
Quick Start with Curl (Works with Any API)
The fastest way to test any currency API is with curl. Here is an example using our API:
# Convert 100 USD to EUR — no API key needed
curl -s "https://www.currencyexchangetool.com/api/convert?amount=100&from=USD&to=UAH"
# Get all supported currencies
curl -s "https://www.currencyexchangetool.com/api/v1/currencies" | jq '.currencies[].code'Why “No API Key” Matters
Requiring an API key creates friction at every stage of development:
- Prototyping: You have to stop coding, navigate to a registration page, fill in a form, verify an email, and paste a key back into your code.
- Open source: You cannot commit a working example to a public repository without exposing your API key.
- CI/CD: API keys need to be added to environment variables in every build pipeline.
- Education: Every student following a tutorial needs their own key, adding a barrier to learning.
An API that requires no key is dramatically easier to use, share, and deploy. This is why we believe the best free currency API is one that simply works — no strings attached.
Frequently Asked Questions
Do I really not need an API key?
Not for our API or Frankfurter, MoneyConvert, and ExchangeRate-API (open endpoint). Our API is completely anonymous — just make a GET request. V1 endpoints are rate-limited per IP but do not require authentication.
Which free API has the most currencies?
MoneyConvert supports 182+ currencies. Our API supports 92 via the V1 endpoint. Frankfurter covers 201 currencies but only ~30 are updated daily from the ECB.
Can I use a free currency API in production?
Yes. All the APIs listed above are used in production applications. For high-traffic applications, consider the rate limits and update frequency carefully. Our API V1 provides production-ready features like CORS headers and structured error responses.
Which free currency API is best for Google Sheets?
Our API supports format=xml for use with Google Sheets IMPORTXML, making it the easiest to integrate for spreadsheet automation. ExchangeRate-API also supports this format.
What about cryptocurrency APIs?
For cryptocurrency rates, CoinGecko offers a generous free API. Some fiat currency APIs (like UniRateAPI) also include crypto coverage. Our API currently supports fiat currencies only.
Final Verdict
After comparing all the major free currency exchange APIs in 2026, here is our recommendation:
- If you want zero friction and live rates → use Currency Exchange Tool API
- If you need unlimited requests with ECB coverage → use Frankfurter
- If you need broad currency coverage with a free signup → use ExchangeRate-API (free key tier)
- If you need crypto + fiat in one API → use UniRateAPI
- If you want an MCP server for AI → use Frankfurter
The best API is the one that fits your project's specific constraints. Start with the simplest option (no-key, no-signup) and upgrade only when you need features like higher rate limits or dedicated support.