Migration Guide: CurrencyAPI to fastFOREX API

Migrate from CurrencyAPI in under an hour

CurrencyAPI nests each rate inside a per-currency object; fastFOREX API returns a flat map. Beyond that one parsing change, every endpoint has a direct equivalent, mapped below.

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Four steps, most of them small.

Get a free API key
7-day trial, no credit card, full plan access from minute one.
Swap base URL & auth
api.currencyapi.com/v3 to api.fastforex.io, and ?apikey= becomes the X-API-Key header (or ?api_key=).
Flatten your parser
Their data.EUR.value nesting becomes a flat results.EUR number. One line simpler, not one line different.
Benchmark, then cut over
Run both in parallel on the trial, compare values and freshness, 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

CurrencyAPI

fastFOREX API

Latest rates (specific symbols)

GET /v3/latest?base_currency=USD&currencies=EUR,GBP

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

Latest rates (all currencies)

GET /v3/latest?base_currency=USD

GET /fetch-all?from=USD

Convert an amount

GET /v3/convert?value=100&base_currency=USD&currencies=EUR (paid plans)

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

Historical (single date)

GET /v3/historical?date=2020-01-01

GET /historical?date=2020-01-01

Time-series (date range)

GET /v3/range?datetime_start=…&datetime_end=… (Medium plan and up)

GET /time-series?to=EUR&start=…&end=… (one currency per call)

List currencies

GET /v3/currencies

GET /currencies

Quota / account status

GET /v3/status

GET /usage

Authentication

?apikey=YOUR_KEY

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

Response shapes

Before and after.

Their response nests each currency in an object (data.EUR.value). Ours is a flat map (results.EUR). Delete the .value hop and the parser is done.

Before · CurrencyAPI

$ curl "https://api.currencyapi.com/v3/
   latest?apikey=KEY&currencies=EUR,GBP"

{
  "meta": { "last_updated_at":
            "2026-09-10T09:38:59Z" },
  "data": {
    "EUR": { "code": "EUR", "value": 0.8599 },
    "GBP": { "code": "GBP", "value": 0.7299 }
  }
}

After · fastFOREX API

$ curl -H "X-API-Key: YOUR_KEY" \
   "https://api.fastforex.io/fetch-multi?from=USD&to=EUR,GBP"

{
  "base": "USD",
  "results": {
    "EUR": 0.8599,
    "GBP": 0.7299
  },
  "updated": "2026-09-10T09:39:00Z",
  "ms": 5
}

Watch for these differences.

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

Update frequency changes underneath you
CurrencyAPI's cheaper tiers refresh hourly; 60-second updates start at $39.99/mo. fastFOREX API updates every 60 seconds on One, every 30 on Extra and every second on Premium, so revisit any client-side caching tuned to hourly data.
The meta wrapper disappears
Timestamps move from meta.last_updated_at to a top-level updated field, already in ISO-8601. No format change, just a shorter path.
Conversion on every plan
CurrencyAPI's /v3/convert needs a paid plan. Ours is on every plan and returns the converted amount alongside the rate used, so client-side conversion maths can go.
Check currency coverage
CurrencyAPI lists ~170 currencies including some crypto codes. Diff /currencies (and /crypto/currencies for crypto) against your usage before cutover.

Prove it to yourself

Compare what matters during your trial.

Run both APIs side by side for 7 days. These are the three things worth checking.

Fresh rates

New rates every 60s, 30s or 1s, depending on your plan.

How to check: compare the updated time on each response.

Bid/ask

Deeper data

Bid and ask from institutional sources, not just a midpoint.

How to check: compare the fields each response gives you.

4ms

Fast servers

Average time from a request reaching our servers to the response leaving.

How to check: read the ms field in every response.

Switching support included

Our team is here to help with your migration, 365 days a year. Need longer than 7 days to validate? Ask about extending your trial.

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Need faster updates? Stream rates live over WebSockets.

Migration questions.

What teams ask when leaving CurrencyAPI.

Can I run both APIs in parallel?

Yes, it's the recommended path. The 7-day trial has full plan access, so shadow-read against both providers and compare values and freshness on production traffic before switching.

Will values match CurrencyAPI's exactly?

Close but not identical. We use different source networks and snapshot times, and their cheaper tiers snapshot hourly. We aggregate 100+ named institutional contributors continuously. Benchmark both against a reference you trust.

I'm on their free tier. Why pay at all?

If a few hundred hourly calls cover you, free tiers are fine. Teams switch when they need fresher data, more calls, or someone to answer when it breaks. Our support answers 365 days a year.

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

Migrate from CurrencyAPI in under an hour

Four steps, most of them small.

Get a free API key

Swap base URL & auth

Flatten your parser

Benchmark, then cut over