Skip to main content

✨ fastFOREX API MCP is now Generally Available - let your agents manage your fastFOREX API ✨

Migration Guide — ExchangeRatesAPI.io → fastFOREX API

Migrate from ExchangeRatesAPI.io in under an hour

ExchangeRatesAPI.io shares its structure with its APILayer siblings — same auth pattern, same rates field, same EUR base lock on lower tiers. That makes the mapping short and the cutover quick.

Create Your Free API KeySee the comparison

Draft guide — endpoint mapping to be validated against both APIs' current docs before publishing.

Four steps, most of them small.

  1. Get a free API key

    7-day trial, no credit card, full plan access from minute one.

  2. Swap base URL & auth

    api.exchangeratesapi.io/v1 → api.fastforex.io, and ?access_key= becomes the X-API-Key header (or ?api_key=).

  3. Rename two fields

    Their "rates" is our "results"; their unix "timestamp" is our ISO-8601 "updated". Drop the "success" flag check — we use HTTP status codes.

  4. Benchmark, then cut over

    Run both in parallel on the trial, compare values and latency, switch when convinced.

Endpoint mapping

Every endpoint, translated.

One row per call your code makes today. Parameters keep their meaning — only names and paths change.

Purpose

ExchangeRatesAPI.io

fastFOREX API

Latest rates (specific symbols)

GET /v1/latest?symbols=USD,GBP

GET /fetch-multi?from=EUR&to=USD,GBP

Latest rates (all currencies)

GET /v1/latest

GET /fetch-all?from=EUR

Convert an amount

GET /v1/convert?from=USD&to=EUR&amount=100 (paid tiers)

GET /convert?from=USD&to=EUR&amount=100 (every plan)

Historical (single date)

GET /v1/2020-01-01 (date as path)

GET /historical?date=2020-01-01

Time-series (date range)

GET /v1/timeseries?start_date=…&end_date=… (paid tiers)

GET /time-series?start=…&end=… (every plan)

Fluctuation

GET /v1/fluctuation (paid tiers)

Compute from /time-series, or use /fx OHLC endpoints

List currencies

GET /v1/symbols

GET /currencies

Authentication

?access_key=YOUR_KEY

X-API-Key header (keeps keys out of logs)

Response shapes

Before and after.

Typically one line changes: data.rates becomes data.results. Drop the "success" boolean check — fastFOREX API signals errors with HTTP status codes, so your HTTP client already handles them.

Before · ExchangeRatesAPI.io
$ curl "https://api.exchangeratesapi.io/v1/
   latest?access_key=KEY&symbols=USD,GBP"

{
  "success": true,
  "timestamp": 1757490000,
  "base": "EUR",
  "date": "2026-09-10",
  "rates": {
    "USD": 1.163,
    "GBP": 0.849
  }
}
After · fastFOREX API
$ curl -H "X-API-Key: YOUR_KEY" \
   "https://api.fastforex.io/fetch-multi?from=EUR&to=USD,GBP"

{
  "base": "EUR",
  "results": {
    "USD": 1.163,
    "GBP": 0.849
  },
  "updated": "2026-09-10T09:39:00Z"
}

Watch for these differences.

The honest list — everything that behaves differently, including the ones that work in your favour.

  1. EUR base lock disappears

    Lower tiers fix EUR as base; changing base is a paid feature. Every fastFOREX API plan supports any base — client-side cross-rate maths can be deleted.

  2. Feature gates fall away

    Convert, time-series and fluctuation are paid-tier features there. Here every endpoint is on every plan — the only variables are call volume and update speed.

  3. The success flag

    Like its APILayer siblings, it returns 200 OK with {"success": false} on errors. We return real HTTP error codes — check your error handling isn't reading the body for failures.

  4. Keys move out of URLs

    ?access_key= puts credentials in URLs, logs and referrer headers. The X-API-Key header keeps them out — and you can create, label and rotate keys in the Console.

Prove it to yourself

Benchmark both during your trial.

Don't take our 21ms average on faith. Run both APIs from your own infrastructure with this snippet, compare the numbers, and cut over when the data says so.

benchmark.sh · run from your servers
$ for i in 1 2 3 4 5; do
>   curl -s -o /dev/null -w "fastforex         %{time_total}s\n" \
>     -H "X-API-Key: KEY" "https://api.fastforex.io/fetch-all?from=EUR"
>   curl -s -o /dev/null -w "exchangeratesapi  %{time_total}s\n" \
>     "https://api.exchangeratesapi.io/v1/latest?access_key=KEY"
> done

fastforex         0.022s
exchangeratesapi  0.049s

Switching support included.

Our team answers 365 days a year and has guided many migrations from this exact provider. Need longer than 7 days to validate? Ask about extending your trial.

Create Your Free API KeyTalk to Support

Migration questions.

What teams ask when leaving ExchangeRatesAPI.io.

Can I run both APIs in parallel?
Yes — the recommended path. The 7-day trial has full plan access, so shadow-read against both providers and compare values and latency on production traffic before switching.
Will values match exactly?
Close but not identical — different source networks and snapshot times. We aggregate 100+ named institutional contributors continuously. Benchmark both against a reference you trust.
Is this the same as migrating from Fixer?
Nearly — ExchangeRatesAPI.io, Fixer and CurrencyLayer are all APILayer products with similar structures. If you use more than one, a single parser change covers the lot. See the Fixer and CurrencyLayer guides for their specifics.
Can you help with the migration?
Yes — support answers 365 days a year. If you need more than 7 days to validate, ask about extending your trial.

Something specific to your setup?

Send us your current integration details and we'll map it for you.

Contact Support

An hour of work for 60x fresher data.

Get your free API key and run fastFOREX API alongside your current provider today.

Create Your Free API Key