Do I need an API key to get exchange rates in Python?

No. You can call /v1/latest/{base} anonymously to start. Anonymous calls are rate-limited per IP address, so for production use you should sign up for a free key, which raises the limit to 10,000 calls a month at 12 requests a minute.

How do I pass my API key in a Python request?

Send it as a bearer token in the Authorization header, for example {"Authorization": "Bearer exr_live_..."}. An X-API-Key header is also accepted for platforms that cannot set Authorization.

Which currencies does the API return?

A single /v1/latest call returns rates for 31 currencies against your chosen base. You can also convert between any supported pair with /v1/convert, including triangulated crosses.

Tutorial/Python quickstart

How to get exchange rates in Python

Q: Are the rates suitable for executing trades?

No. The rates are indicative, published for reference, analytics, and display. They are not a dealing quote. Every response says so in its notice field.

Read live and historical FX rates in Python with a few lines of code. No key to start, 10,000 calls a month once you sign up, and every response tells you how fresh the rate is.

ERexchangerate.dev·Updated Sep 8, 2026·5 min read

The shortest path to exchange rates in Python is a GET request to /v1/latest/USD. You get back JSON with rates across the supported 31-currency catalog, with per-currency sources and effective_at metadata. No API key is required to make your first call.

Key points

One GET to /v1/latest/{base} returns rates for 31 currencies as JSON.

Use sources[currency] and effective_at[currency] to describe the displayed currency; market_session describes the trading session.

The free tier is 10,000 calls a month at 12 requests a minute, no card required.

Rates are indicative, published for reference and analytics, not as a dealing quote.

Your first call, no dependencies

You need nothing beyond the standard library. urllib.request handles a single call. To build a complete threshold monitor with saved state, see exchange-rate alerts in Python. Start with this request:

python · standard librarycopy

import json
from decimal import Decimal
import urllib.request

url = "https://api.exchangerate.dev/v1/latest/USD?symbols=EUR,GBP"
with urllib.request.urlopen(url, timeout=10) as response:
    data = json.load(response, parse_float=Decimal)

print(data["rates"]["EUR"])
print(data["sources"]["EUR"], data["effective_at"]["EUR"])
print(data["market_session"])

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. Install requests, set EXCHANGERATE_API_KEY in your server environment, and pass the key as a bearer token:

python · requestscopy

# Install first: python -m pip install requests
import os
from decimal import Decimal
import requests

response = requests.get(
    "https://api.exchangerate.dev/v1/latest/USD",
    headers={"Authorization": f"Bearer {os.environ['EXCHANGERATE_API_KEY']}"},
    timeout=10,
    allow_redirects=False,
)
if response.status_code == 429:
    raise RuntimeError(f"Rate limited; Retry-After: {response.headers.get('Retry-After')}")
if 300 <= response.status_code < 400:
    raise RuntimeError("Unexpected redirect")
response.raise_for_status()
data = response.json(parse_float=Decimal)
print(data["rates"]["GBP"], data["effective_at"]["GBP"])

A free key raises your limit to 10,000 calls a month at 12 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:

python · convert 100 USD to EURcopy

import os
from decimal import Decimal
import requests

response = requests.get(
    "https://api.exchangerate.dev/v1/convert/USD/EUR/100",
    headers={"Authorization": f"Bearer {os.environ['EXCHANGERATE_API_KEY']}"},
    timeout=10,
    allow_redirects=False,
)
if not 200 <= response.status_code < 300:
    raise RuntimeError(f"HTTP {response.status_code}; Retry-After: {response.headers.get('Retry-After')}")
data = response.json(parse_float=Decimal)
print(data["rate"], data["converted"])

Know how fresh a rate is

For a displayed currency, read sources[currency] and effective_at[currency]. The aggregate source field describes the least-fresh contributing data. 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 is open, weekend, or interbank_closed for a known non-weekend closure.

Field valueWhat it meansWhen it moves

source: liveAggregated spot consensusIntraday (~60s), trading week

source: ecb_dailyOfficial reference fixOnce per business day

market_session: weekendSaturday or Sunday (interbank closed)Reference fix carries Friday's value; live feed not updating

Indicative, not for settlement

Rates are published for reference, analytics, and display. They are not a dealing quote and should not be used to settle a trade. Every response carries this in its notice field.

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:

python · rate on a past datecopy

import os
from decimal import Decimal
import requests

response = requests.get(
    "https://api.exchangerate.dev/v1/2026-03-14/USD?symbols=JPY",
    headers={"Authorization": f"Bearer {os.environ['EXCHANGERATE_API_KEY']}"},
    timeout=10,
    allow_redirects=False,
)
if not 200 <= response.status_code < 300:
    raise RuntimeError(f"HTTP {response.status_code}; Retry-After: {response.headers.get('Retry-After')}")
data = response.json(parse_float=Decimal)
print(data["rates"]["JPY"], data["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.

exchangerate.dev

Integration guides for developers.

Your first call, no dependencies

With requests and an API key

Convert an amount

Know how fresh a rate is

Read a single past day

Keep reading