Skip to main content

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

Migration Guide — ExchangeRate-API → fastFOREX API

Migrate from ExchangeRate-API in under an hour

ExchangeRate-API puts your key in the URL path and returns "conversion_rates"; we use a header and "results". Beyond that, the concepts map one-to-one — and you gain bid/ask, sub-hourly updates and crypto they don't offer.

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. Move your key out of the URL

    Their key lives in the URL path; ours goes in the X-API-Key header — cleaner for logs and proxies.

  3. Rename one field

    Their "conversion_rates" is our "results". Their result:"success" flag becomes plain 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

ExchangeRate-API

fastFOREX API

Latest rates (all currencies)

GET /v6/YOUR-KEY/latest/USD

GET /fetch-all?from=USD

Single pair

GET /v6/YOUR-KEY/pair/EUR/GBP

GET /fetch-one?from=EUR&to=GBP

Convert an amount

GET /v6/YOUR-KEY/pair/EUR/GBP/100

GET /convert?from=EUR&to=GBP&amount=100

Historical (single date)

GET /v6/YOUR-KEY/history/USD/2020/1/1

GET /historical?date=2020-01-01

Time-series (date range)

— (loop daily history calls)

GET /time-series?start=…&end=… (one call)

List currencies

GET /v6/YOUR-KEY/codes

GET /currencies

Enriched data (symbols, names)

GET /v6/YOUR-KEY/enriched/… (Business)

GET /currencies (every plan)

Authentication

Key embedded in URL path

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

Response shapes

Before and after.

data.conversion_rates becomes data.results, and base_code becomes base. Their unix timestamps become one ISO-8601 "updated" string — Date.parse() handles it natively.

Before · ExchangeRate-API
$ curl "https://v6.exchangerate-api.com/
   v6/YOUR-KEY/latest/USD"

{
  "result": "success",
  "time_last_update_unix": 1757490000,
  "base_code": "USD",
  "conversion_rates": {
    "EUR": 0.859587,
    "GBP": 0.738035
  }
}
After · fastFOREX API
$ curl -H "X-API-Key: YOUR_KEY" \
   "https://api.fastforex.io/fetch-all?from=USD"

{
  "base": "USD",
  "results": {
    "EUR": 0.859587,
    "GBP": 0.738035
  },
  "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. Keys in URLs leak

    Their key sits in every request path, which means it lands in server logs, proxies and browser history. Moving to our X-API-Key header is a small security upgrade for free.

  2. Freshness assumptions change a lot

    Their Pro plan updates hourly and Business every 5 minutes. At 60-second (or 1-second) updates, any caching you built around hourly data can be rethought — or deleted.

  3. No time-series endpoint to replace

    If you loop daily history calls to build ranges, replace the loop with one /time-series call — up to 100 points per request.

  4. Trading-grade data is new territory

    By their own docs, their rates are 'unsuitable for forex trading' with no spread data. If you've been wanting bid/ask or OHLC, /fx/quote and /fx/ohlc/time-series are now available to you.

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=USD"
>   curl -s -o /dev/null -w "era       %{time_total}s\n" \
>     "https://v6.exchangerate-api.com/v6/KEY/latest/USD"
> done

fastforex 0.020s
era       0.061s

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 ExchangeRate-API.

Can I run both APIs in parallel?
Yes — the recommended path. Shadow-read against both during the 7-day trial and compare values and latency before switching.
They promise LTS — do you?
Yes, and it's policy: existing endpoints are never changed in breaking ways; evolution ships as new endpoints or versioned paths. See our Reliability & Security page for the full commitment.
Will values match exactly?
Close but not identical — they blend central-bank reference data; we aggregate live institutional contributors. Our rates track the trading market more closely intraday.
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