Banco de México Exchange Rate API: The Official FIX Rate as JSON

Banco de México determines the FIX rate from wholesale market quotes each banking day and releases it from noon. It is not merely a reference number: under Circular 3/2012 the FIX is the rate that legally settles US dollar obligations payable in Mexico. If you invoice, pay, or report in dollars against a Mexican counterparty, this is the rate that decides the peso amount.

What Banco de México publishes

• The FIX rate (USD/MXN) — determined from wholesale quotes for settlement on the second following banking day, released from 12:00 Mexico City time.
• History back to January 1993 — the entire nuevo peso era, 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 Mexican banking holidays resolve to the most recent published rate and are flagged explicitly.

Why the FIX is not just another USD/MXN quote

A live mid-market feed answers "what is USD/MXN trading at right now?" — the right tool for a checkout or a dashboard. Mexican tax, customs, and contract law ask a different question: "which rate were you required to use on that date?" The FIX is the answer, and it has a specific publication chain that matters if anyone ever audits the number.

Banxico determines the FIX on day one, publishes it in the Diario Oficial de la Federación on the next banking day, and it applies to obligations settled the day after that publication. Those are three distinct dates. This API stores the FIX under its determination date — the date everyone means when they say "the FIX for 3 March" — so you always know which number you are citing.

Get the latest rate (REST)

curl "https://allratestoday.com/api/v1/central-bank/banxico/latest?source=USD&target=MXN" \
  -H "Authorization: Bearer YOUR_API_KEY"

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

No Banxico token required

Banco de México runs its own SIE REST API, and it is a perfectly good API — but it gates access behind a registered token, which means a signup step, a credential to store, and a second integration to maintain if you already consume other central banks. AllRatesToday serves the same official FIX values through the same endpoints, response shape, and SDK surface as the other 34 central banks in the catalogue, so Mexico is not a special case in your codebase.

The npm SDK

npm install banxico-exchange-rate

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

// The official FIX rate
const pair = await getRate('USD', 'MXN', { 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 'banxico-exchange-rate';

// The official rate 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: 'MXN', from: '2026-01-01' },
  { apiKey: 'art_live_...' }
);

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

Official, informational, and derived

Banxico also publishes peso rates against the euro, the Japanese yen, and the Canadian dollar — and labels them, in its own footnotes, "estrictamente informativos y sin carácter oficial". They are cross rates built from the FIX plus IMF market rates, with the Canadian figure taken from the Bank of Canada. This API keeps that distinction: those rates carry a distinct type, and are never dressed up as official published rates.

The same honesty applies to pairs the bank never printed. If you ask for one, the API resolves it from the published table — an inverse, or a cross via MXN — and flags it derived: true with the method used. For a compliance filing that distinction is the whole point.

The full nuevo peso era, 1993 to today

The series starts in January 1993, when the nuevo peso replaced the old peso at a thousand to one. From there the official record runs straight through the December 1994 devaluation that began the Tequila crisis — the FIX moves from 3.4662 on 19 December to 4.8875 on 22 December — the 1995 peak above 7, the 2008 financial crisis, the 2016 US election, and the March 2020 pandemic spike to 25.1185, still the weakest the peso has ever closed against the dollar. Every one of those numbers is the rate Banxico actually published on the day.

FAQ

Does Banco de México have an exchange rate API?

Banxico publishes its own SIE REST API, but it requires you to register for a token first. AllRatesToday serves the same official FIX rate in the unified multi-bank format used by 34 other central banks, with no separate registration — via REST or the banxico-exchange-rate npm package, with history back to 1993. The latest rate is free.

What is the FIX rate and when is it published?

The FIX is determined by Banco de México from wholesale market quotes for settlement on the second following banking day. It is released from noon each banking day and published in the Diario Oficial de la Federación the next banking day. Under Circular 3/2012 it is the rate that legally settles US dollar obligations payable in Mexico.

Can I get the Banxico FIX rate for a past invoice date?

Yes. Historical dates go back to January 1993, the start of the nuevo peso. Weekends and Mexican banking holidays resolve to the most recent published date and are flagged, so your audit trail stays honest. Historical dates require a paid plan; the latest rate is free.