AllRatesToday vs Fixer.io vs XE.com vs ExchangeRate-API: The 2026 Exchange Rate API Comparison

Choosing an exchange rate API is a boring decision with expensive consequences. Pick one with stale data and your checkout shows prices 2% off the market. Pick one with a tight free tier and you hit a wall the day you launch. Pick one with EUR-only base currencies and you spend the next sprint rewriting conversion logic.

This article compares the four most-searched exchange rate APIs of 2026 — AllRatesToday, Fixer.io, XE.com, and ExchangeRate-API — across the criteria that actually matter: update frequency, latency, HTTPS, currency coverage, historical data, CORS, and free-tier limits.

TL;DR — Quick Comparison Table

Real-Time Updates: How Fresh Is the Data?

Update frequency is the first question to ask about any exchange rate API, because it determines whether the data is usable for real-money decisions.

• AllRatesToday refreshes every 60 seconds from Reuters/Refinitiv and interbank feeds.
• XE.com also runs 60-second updates, backed by 30+ years of FX aggregation.
• Fixer.io updates hourly on most tiers, sourced from the European Central Bank.
• ExchangeRate-API updates daily on the free plan.

For trading, payments, or any flow where the rate affects the amount charged, hourly or daily updates are not enough. During volatile sessions, a major pair can move 1% in minutes — and that gap comes out of your margin or your customer's pocket.

Latency: How Fast Does the API Respond?

• ExchangeRate-API ~134ms — fastest overall, thanks to aggressive CDN caching of daily snapshots.
• AllRatesToday ~214ms — fastest among real-time providers.
• Fixer.io ~342ms.
• XE.com ~471ms — slowest in the group.

ExchangeRate-API wins on raw speed, but it's apples-to-oranges: cached daily data will always respond faster than live data. Among APIs serving real-time rates, AllRatesToday is the fastest by a clear margin.

HTTPS and Security

HTTPS should be table stakes in 2026. It isn't, quite.

• AllRatesToday, XE, ExchangeRate-API — HTTPS on every plan.
• Fixer.io — HTTP-only on the free tier. HTTPS is a paid feature.

If you're on Fixer's free plan and your app runs on HTTPS (which it should), you'll hit mixed-content errors the moment you try to fetch rates from the browser. You'll either pay to upgrade or proxy requests through your backend.

Currency Coverage

• Fixer, XE: 170+ currencies.
• AllRatesToday: 160+ currencies plus precious metals.
• ExchangeRate-API: 160+ currencies.

Coverage differences are marginal unless you need exotic pairs or crypto. For everyday FX (USD, EUR, GBP, JPY, major emerging markets), all four are equivalent.

Base Currency Flexibility

This is where Fixer.io falls apart for non-European use cases.

• AllRatesToday, XE, ExchangeRate-API — any base currency on any plan.
• Fixer.io — EUR only on the free tier. Switching base currency is a paid feature.

If you're building a US, Asian, or LATAM product, Fixer's free tier forces you to fetch EUR-based rates and do the cross-rate math in application code. It works, but it's an unnecessary source of rounding bugs.

Historical Rates

Historical rates are needed for accounting, tax reporting, backtesting, and trend analysis.

• AllRatesToday — free on every plan.
• Fixer, XE, ExchangeRate-API — paid plans only.

This is AllRatesToday's biggest free-tier differentiator. Every other provider gates historical data behind a subscription, typically starting at $10–$15/month. If you're building a dashboard, a monthly P&L converter, or anything that touches past rates, that's a real cost difference.

CORS Support

If you're calling the API directly from the browser — landing pages, SPAs without a backend, embedded widgets — CORS support matters.

• AllRatesToday, ExchangeRate-API — CORS enabled.
• Fixer, XE — no CORS. Browser calls fail without a proxy.

XE and Fixer assume a server-side integration. For static sites, Jamstack projects, or anywhere a backend feels like overkill, AllRatesToday and ExchangeRate-API are the only workable options of the four.

Uptime SLA

All four providers publish 99.9%+ SLAs. 99.95% vs 99.9% is 4 hours of extra uptime per year on paper. In practice, real outages usually beat the SLA numbers anyway, and what matters more is how the provider handles incidents — status page, postmortems, response times. Check status page history rather than the marketing-page SLA.

Free Tier: What You Actually Get

• AllRatesToday — free forever. 300 requests/month, all endpoints (including historical), all base currencies, HTTPS, CORS.
• ExchangeRate-API — free forever. 1,500 requests/month, daily updates, no historical on free.
• Fixer.io — free but constrained. 100 requests/month, hourly updates, EUR base only, HTTP only.
• XE.com — trial only. Permanent use requires a paid annual plan.

ExchangeRate-API wins on raw request quota (1,500 vs 300), but the data is daily snapshots. AllRatesToday's 300 free requests include real-time rates, historical data, and flexible base currencies — a different kind of generosity.

When to Use Each API

Use AllRatesToday when

• You need real-time rates without paying for them.
• You need historical data on a free tier.
• You're calling from the browser (CORS).
• You want flexible base currencies.

Use ExchangeRate-API when

• Daily rates are good enough.
• You need high request volume on the free tier.
• You want the fastest response times.

Use Fixer.io when

• You're a European product and EUR-base is natural.
• You need ECB-aligned data for regulatory reasons.
• You're already on a paid plan and the ecosystem fits.

Use XE.com when

• You're an enterprise with an annual budget.
• You need XE's brand recognition or ERP integrations (SAP, Oracle, MS Dynamics).
• Multi-asset coverage (FX + metals + select crypto) matters.

The Bottom Line

For most developers in 2026, AllRatesToday is the best default:

• Real-time rates (60-second updates from Reuters/Refinitiv).
• Historical data on the free tier.
• Any base currency, HTTPS, CORS out of the box.
• 99.9% uptime and sub-250ms latency.

Fixer remains viable if you're already in its ecosystem. XE is for enterprises with budgets. ExchangeRate-API is the right call when you only need daily rates and want the highest free quota.

FAQ

Which exchange rate API is the most accurate?

Accuracy tracks the data source. Providers using Reuters/Refinitiv or interbank feeds (AllRatesToday, XE) deliver tighter mid-market rates than providers using ECB end-of-day snapshots (Fixer, ExchangeRate-API on the free tier).

Which exchange rate API has the best free tier?

Depends on the axis. ExchangeRate-API has the highest request cap (1,500/month). AllRatesToday has the richest feature set: real-time, historical, any base, CORS, HTTPS.

Can I use these APIs from the browser?

AllRatesToday and ExchangeRate-API support CORS out of the box. Fixer and XE do not — you'll need a server-side proxy.

Do these APIs support cryptocurrency?

XE covers select cryptocurrencies. The other three are fiat-focused. For crypto-heavy use cases, consider a dedicated crypto API.

Which API is cheapest for historical rates?

AllRatesToday — historical rates are included on the free tier. Every other provider in this comparison charges for historical data.