Hong Kong dollar (HKD) exchange rate API

Hong Kong is a major international financial center, and its currency works differently from most: the Hong Kong dollar is tied to the US dollar through a currency board arrangement. For developers this means USD/HKD is almost constant, while HKD/EUR, HKD/JPY or HKD/CNY move with the dollar. The fxapi HKD exchange rate API returns all of them, and the peg makes a good automated sanity check for your data pipeline.

HKD facts for developers

• Where it’s used: Hong Kong. It is also widely accepted in Macau, whose pataca (MOP) is in turn linked to the Hong Kong dollar.
• Symbol and formatting: $, written HK$ to distinguish it from other dollars. Format: HK$1,234.50.
• Minor unit: 2 decimals (cents).
• Issuer: the Hong Kong Monetary Authority (HKMA) runs the currency board. Banknotes are issued by three commercial banks – HSBC, Standard Chartered and Bank of China (Hong Kong) – plus the government’s own HK$10 note.
• Regime: the Linked Exchange Rate System has fixed the Hong Kong dollar to the US dollar since 1983, originally at 7.80. On 18 May 2005 – the sample date on this page – the HKMA introduced a strong-side Convertibility Undertaking at 7.75 and announced that the weak side would move from 7.80 to 7.85 (completed on 20 June 2005), creating today’s band symmetric around 7.80.
• Events in the historical data: before the 2005 refinements there was no formal strong-side limit, so a band check should only run on dates after mid-2005. The interesting moves are in HKD’s rates against other currencies, which mirror the US dollar.

Get HKD rates with the fxapi API

/v1/latest works on every plan, and Professional and Enterprise refresh it every 60 seconds. This Ruby script fetches USD/HKD and raises an alert if a value falls outside the band – a cheap check that your rate feed and parsing are sane:

require "net/http"
require "json"

BAND = (7.75..7.85)

uri = URI("https://api.fxapi.com/v1/latest")
uri.query = URI.encode_www_form(base_currency: "USD", currencies: "HKD,CNY,EUR")
req = Net::HTTP::Get.new(uri)
req["apikey"] = ENV.fetch("FXAPI_KEY")

res = Net::HTTP.start(uri.host, uri.port, use_ssl: true) { |http| http.request(req) }
raise "fxapi returned #{res.code}" unless res.is_a?(Net::HTTPSuccess)

body = JSON.parse(res.body)
data = body["data"]
usd_hkd = data.dig("HKD", "value")

warn "USD/HKD #{usd_hkd} outside 7.75–7.85 – check your feed" unless BAND.cover?(usd_hkd.round(4))

# Cross rate: HKD per 1 EUR, derived through USD
puts format("USD/HKD %.4f  EUR/HKD %.4f  (as of %s)",
            usd_hkd, usd_hkd / data.dig("EUR", "value"), body.dig("meta", "last_updated_at"))

The cross rate is derived through the dollar – learn how in base currency and cross rates. For a plain feed of live values see the real-time exchange rates API, and for back-dated checks the historical exchange rates API. The Ruby guide covers retries and caching, and the US dollar page lists other dollar pegs.

Things to watch

• Allow tiny tolerance. Market rates can touch the band edges; compare with a rounded value rather than strict equality.
• CNY vs CNH. Hong Kong is the main offshore yuan market (CNH), but fxapi lists the yuan only under its ISO code CNY.
• Same $ sign. Show HK$ or HKD next to prices that could be read as US dollars.

Popular HKD pairs

Request any of these pairs – or any other combination of the 190+ supported currencies – with base_currency=HKD:

Monthly averages and fluctuation for HKD

# Monthly average HKD rates for 2025 (IAS 21 / ASC 830)
curl -G "https://api.fxapi.com/v1/average" \
  -d date_from=2025-01-01 -d date_to=2025-12-31 -d period=month \
  -d base_currency=HKD -d currencies=USD,CNY,EUR \
  -H "apikey: $FXAPI_KEY"

# How did HKD move over the last year?
curl -G "https://api.fxapi.com/v1/fluctuation" \
  -d date_from=2025-10-01 -d date_to=2026-10-01 \
  -d base_currency=HKD -d currencies=USD,CNY,EUR \
  -H "apikey: $FXAPI_KEY"

See the historical exchange rates API, average rates API and documentation for every parameter.

HKD is one of 190+ currencies in fxapi, the foreign exchange rates API for developers – live rates, daily history since 1999 and monthly averages with one API key.

Frequently asked questions