E.SUN Bank Exchange Rate API: TWD Buy and Sell Rates as JSON

E.SUN Commercial Bank is one of Taiwan’s largest private banks and a major retail FX provider. Its rates page lists spot and cash buy/sell rates for 15 currencies against the NT dollar, with a time stamp on every quote. This guide shows how to read that board as JSON: what the rates mean, how they compare with the Central Bank of the Republic of China (Taiwan) official rate and with other banks in Taiwan, and the calls that return them.

What the E.SUN board shows

• 15 currencies against the New Taiwan dollar: AUD, CAD, CHF, CNY, EUR, GBP, HKD, JPY, MXN, NZD, SEK, SGD, THB, USD and ZAR. Every value is TWD per 1 unit of the foreign currency.
• The spot (transfer) buy / sell pair. Taiwan’s central bank publishes one exchange-rate series of its own, the NT dollar/US dollar interbank close, so for every other currency the reference people use is a bank board. Banks quote a spot (transfer) pair and a cash pair; the pair here is the spot one, which a remittance or account transfer is converted at. Boards update from 09:00 to 15:30 Taipei time. Bank of Taiwan’s board, the best known, sits behind a bot challenge and is not collected.
• USD on 13 November 2026: E.SUN bought at 32.8 and sold at 32.9 TWD, a spread of 0.30%. The Central Bank of the Republic of China (Taiwan) official rate was 32.838, so the bank's mid sat +0.04% from it.
• The bank's own timestamp. The page prints a last-updated stamp (2026-11-13T21:35:20+08:00 on the board above), returned as bank_updated_at next to our captured_at.
• Every day's board is kept permanently, from 20 October 2026. Read one past day with ?date=, or a range for one currency with the /history endpoint (paid plans).

Spreads across the board

On the 13 November 2026 board the tightest spreads were USD (0.30%), SGD (0.63%), CHF (0.66%) and the widest ZAR (5.14%), MXN (4.51%), THB (4.12%). Spread is (sell − buy) ÷ mid: what a round trip through the bank costs, before any fees. The API returns it on every row as spread_pct, so you can rank currencies or alert when a bank widens its board.

USD at E.SUN and other banks in Taiwan

USD on the 3 boards AllRatesToday reads in Taiwan, all captured on 13 November 2026 (the Central Bank of the Republic of China (Taiwan) official rate was 32.838):

E.SUN had the narrowest USD spread of the 3. One call to /api/v1/bank-rates/tw returns every board in the table at once.

Get the board (REST)

You need an API key; the free key works. The full board:

curl "https://allratestoday.com/api/v1/bank-rates/tw/esun" \
  -H "Authorization: Bearer art_live_your_key"

What comes back (the 13 November 2026 board, first three rows):

{
  "bank": "esun",
  "name": "E.SUN Bank",
  "country": "tw",
  "quote_ccy": "TWD",
  "bank_updated_at": "2026-11-13T21:35:20+08:00",
  "basis": "Spot (transfer) buy / sell",
  "captured_at": "2026-11-13T13:35:41.037Z",
  "rates": [
    {"ccy":"AUD","buy":22.23,"sell":22.45,"mid":22.34,"spread_pct":0.985,"official":null,"vs_official_pct":null},
    {"ccy":"CAD","buy":22.97,"sell":23.15,"mid":23.06,"spread_pct":0.781,"official":null,"vs_official_pct":null},
    {"ccy":"CHF","buy":39.12,"sell":39.38,"mid":39.25,"spread_pct":0.662,"official":null,"vs_official_pct":null},
    … 12 more currencies
  ],
  "disclaimer": "…",
  "attribution": { … }
}

One currency, with the row fields at the top level:

curl "https://allratestoday.com/api/v1/bank-rates/tw/esun?ccy=USD" \
  -H "Authorization: Bearer art_live_your_key"

{
  "bank": "esun",
  "name": "E.SUN Bank",
  "country": "tw",
  "quote_ccy": "TWD",
  "bank_updated_at": "2026-11-13T21:35:20+08:00",
  "basis": "Spot (transfer) buy / sell",
  "captured_at": "2026-11-13T13:35:41.037Z",
  "ccy": "USD",
  "buy": 32.8,
  "sell": 32.9,
  "mid": 32.85,
  "spread_pct": 0.304,
  "official": 32.838,
  "vs_official_pct": 0.037,
  "disclaimer": "Retail buy/sell rates as displayed on each bank’s own website at capture time, quoted as home currency per 1 unit of foreign currency. Indicative only: banks change these through the day, apply them at the counter or in-app, and they are not official or reference rates. For the rate a regulation names, use the central-bank endpoints.",
  "attribution": {
    "source": "Board rates published by E.SUN Bank on its own website, collected by AllRatesToday",
    "bank_url": "https://www.esunbank.com/zh-tw/personal/deposit/rate/forex/foreign-exchange-rates",
    "url": "https://allratestoday.com/bank-exchange-rate-api/tw/esun/",
    "terms": "Public pages that show the rates need a visible link to allratestoday.com"
  }
}

The board as it stood on a past day:

curl "https://allratestoday.com/api/v1/bank-rates/tw/esun?date=2026-11-06" \
  -H "Authorization: Bearer art_live_your_key"

One currency over a date range, one row per day (paid plans; add &format=csv, xml or xlsx for a file):

curl "https://allratestoday.com/api/v1/bank-rates/tw/esun/history?ccy=USD&from=2026-10-20&to=2026-11-13" \
  -H "Authorization: Bearer art_live_your_key"

JavaScript

npm install @allratestoday/sdk

import { AllRatesToday } from '@allratestoday/sdk';

const client = new AllRatesToday({ apiKey: 'art_live_your_key' });

// E.SUN Bank's USD row
const r = await client.bankRates('tw', { bank: 'esun', ccy: 'USD' });
console.log(`E.SUN buys USD at ${r.buy}, sells at ${r.sell} TWD`);

// The board as it stood on a past day
const past = await client.bankRates('tw', { bank: 'esun', date: '2026-11-06' });
console.log(past.snapshot_date, past.rates.length);

Python

import requests

r = requests.get(
    "https://allratestoday.com/api/v1/bank-rates/tw/esun",
    headers={"Authorization": "Bearer art_live_your_key"},
    timeout=10,
)
r.raise_for_status()
for row in r.json()["rates"]:
    print(row["ccy"], row["buy"], row["sell"], row["spread_pct"])

Board rate or official rate?

The Central Bank of the Republic of China (Taiwan) rate is the one tax, accounting and customs rules in Taiwan name; nobody transacts at it. E.SUN's board is the price a customer actually gets. The API puts both on every row: official is the central bank's rate for the same currency and vs_official_pct is how far the bank's mid sits from it. Use the board to show customers a real price, compare banks for a remittance, or keep a dated record of what the bank quoted; use the Central Bank of the Republic of China (Taiwan) endpoint when a rule asks for the official rate.

FAQ

Where do the E.SUN Bank rates come from?

From the bank's own public rates page (https://www.esunbank.com/zh-tw/personal/deposit/rate/forex/foreign-exchange-rates), read hourly. AllRatesToday does not change the numbers: each row is the buy and sell price E.SUN shows, with the mid, the spread and the Central Bank of the Republic of China (Taiwan) rate added.

Are these the official TWD exchange rates?

No. They are E.SUN's retail prices for customers. The official rate in Taiwan is the Central Bank of the Republic of China (Taiwan) rate, which the API returns as official on each row where the central bank has one, and in full from the central-bank endpoint.

How often is the E.SUN board updated?

AllRatesToday reads the page every hour. The bank's own last-updated stamp is returned as bank_updated_at, so you can tell a fresh read of an unchanged board from a new board.

Can I get E.SUN rates for a past date?

Yes, from 20 October 2026 onward; every day's board is kept permanently. Add ?date=YYYY-MM-DD for one day: the response is the board captured that day, or the nearest earlier day within five days, with date_requested and snapshot_date added. For a range, /history?ccy=USD&from=…&to=… returns one row per day as JSON, CSV, XML or XLSX on paid plans.

Do I need an API key?

Yes. Commercial bank boards need an API key; any plan works, the free key included, and each call counts against the plan. Public pages or widgets that show the rates need a visible link to allratestoday.com.