Monetary Authority of Singapore Exchange Rate API: Official SGD Rates as JSON

The Monetary Authority of Singapore publishes the official exchange rates that accounting, tax, and customs rules in Singapore reference — published official rates, not moving market prices. This guide shows how to pull them as JSON: via a REST endpoint or the zero-dependency mas-exchange-rate npm package.

What the MAS publishes

• 21 currencies against the Singapore dollar — the end-of-period rates from the MAS statistics database.
• History back to 1988 — nearly four decades of official record, queryable by exact date or as a time series.
• The bank's own publication date on every response, so a rate is always citable.
• No gaps to trip over — weekends and Singapore holidays resolve to the most recent published rates and are flagged explicitly.

The USD/SGD rate anchors the table — Singapore runs one of the world's largest FX markets, and IRAS, auditors, and Singapore-invoicing businesses reference the MAS official series.

Why official rates, not market rates

A live mid-market feed answers "what is USD/SGD trading at right now?" — the right tool for checkouts and dashboards. But accountants, auditors, and tax authorities ask a different question: "which rate were you required to use for this date?" That answer comes from the Monetary Authority of Singapore's published rates, and it never changes after publication.

Get the latest rates (REST)

curl "https://allratestoday.com/api/v1/central-bank/mas/latest" \
  -H "Authorization: Bearer YOUR_API_KEY"

The response is the bank's most recent published data — every rate and the publication date. The latest rates are available on every plan, including the free tier (300 requests/month, no credit card).

The npm SDK

npm install mas-exchange-rate

import { getRate, getLatestRates } from 'mas-exchange-rate';

// One pair at the official MAS rate
const pair = await getRate('USD', 'SGD', { apiKey: 'art_live_...' });
console.log(pair.rate, pair.rate_date);

// The bank's full published table
const table = await getLatestRates({ apiKey: 'art_live_...' });
console.log(table.rate_date, table.rates.length);

Zero dependencies, TypeScript types included, and it runs anywhere fetch exists — Node 18+, Bun, Deno, and edge runtimes.

Historical rates for an invoice date

import { getRatesForDate, getHistory } from 'mas-exchange-rate';

// The official rates for an invoice date — non-publication days return
// the most recent published date, flagged via published_on_requested_date.
const day = await getRatesForDate('2026-06-30', { apiKey: 'art_live_...' });

// Time series for one pair
const series = await getHistory(
  { source: 'USD', target: 'SGD', from: '2026-01-01' },
  { apiKey: 'art_live_...' }
);

Historical dates and time series need a paid plan; the latest rates stay free.

Published vs derived pairs

If the MAS does not print a pair directly, the API resolves it from the bank's published rates — an inverse, or a cross rate via SGD — and flags it derived: true with the method used. Official and computed values are never silently mixed, which is exactly the distinction an auditor will ask about.

Four decades of Singapore dollar history

The series starts in 1988 at over 2 SGD per US dollar and documents the long, managed appreciation to the 1.2s — through the Asian financial crisis, the GFC, and every S$NEER policy band shift. For invoice-date lookups, audits, and research it is the official record.

FAQ

Does the Monetary Authority of Singapore have an official exchange rate API?

The MAS publishes its official rates on its own site, and AllRatesToday serves the same published rates as clean JSON via REST or the mas-exchange-rate npm package. The latest table is free.

How often do Monetary Authority of Singapore rates update?

Once per business day — end-of-period rates in the MAS statistics database. These are published official rates, not moving market prices — every API response carries the publication date so you can cite it.

Can I get the MAS rate for a past date, like an invoice date?

Yes. The /central-bank/mas/rates-for-date endpoint returns the official rates for any archived date. Non-publication days resolve to the most recent published date and are flagged, so your audit trail stays honest. Historical dates require a paid plan; latest rates are free.