How to get exchange rates in Python

The shortest path to exchange rates in Python is a GET request to /v1/latest/USD. You get back JSON with rates for 31 currencies plus two freshness fields, source and market_session. No API key is required to make your first call.

Your first call, no dependencies

You need nothing beyond the standard library. urllib.request handles a single call:

import json
import urllib.request

url = "https://api.exchangerate.dev/v1/latest/USD"
with urllib.request.urlopen(url) as resp:
    data = json.load(resp)

print(data["rates"]["EUR"])     # 0.87531
print(data["source"])            # ecb_daily
print(data["market_session"])    # open

That runs without a key. Anonymous calls are capped per IP address, so for anything past a quick test you want a free key.

With requests and an API key

Most projects already use requests. Pass your key as a bearer token:

import requests

API = "https://api.exchangerate.dev/v1"
KEY = "exr_live_..."   # free key at https://exchangerate.dev/signup

resp = requests.get(
    f"{API}/latest/USD",
    headers={"Authorization": f"Bearer {KEY}"},
    timeout=10,
)
resp.raise_for_status()
data = resp.json()

print(data["rates"]["GBP"], data["market_session"])

A free key raises your limit to 50,000 calls a month at 30 requests a minute. The X-API-Key header works too, for platforms that cannot set Authorization.

Convert an amount

To convert rather than list rates, call /v1/convert. It returns the rate and the converted amount together:

r = requests.get(
    f"{API}/convert/USD/EUR/100",
    headers={"Authorization": f"Bearer {KEY}"},
).json()

print(r["rate"])         # 0.87572
print(r["converted"])    # 87.57

Know how fresh a rate is

Two fields on every response tell you what you are looking at. source is the data class: live for aggregated spot, ecb_daily for the European Central Bank reference fix, fred_daily for the Federal Reserve daily series. market_session says whether the FX day is open, weekend, or between sessions.

Read a single past day

Ask for any date back to 1999 by putting it in the path. The response adds is_forward_filled, which is true when no rate was published that day, such as a weekend or holiday:

r = requests.get(
    f"{API}/2026-03-14/USD",
    headers={"Authorization": f"Bearer {KEY}"},
).json()

print(r["rates"]["JPY"], r["is_forward_filled"])

For a full series across a date range in one call, use /v1/range with start_date and end_date. A separate guide covers that.