Monitor Currency Rates for Freelance Invoicing

TL;DR — The Currency Rates Scraper returns the day's exchange rate with date, pair, and provider as JSON. Run it on invoice day, stamp the rate on the bill, and keep a defensible record for cross-border freelance work.

Why freelancers lose money on FX quietly

Cross-border invoices drift on exchange rates in two ways: the rate you assumed when quoting and the rate on the day you bill. With daily FX turnover above $7.5 trillion, a month between quote and invoice can move the real value of your fee by several percent — enough to notice, small enough to never investigate.

The fix is boring: bill at a documented rate. When a client asks why the USD figure moved, you point at the record — date, pair, provider — instead of shrugging.

How does this compare to the alternatives?

The converter website is fine for one invoice. It breaks down when you bill monthly, in three currencies, and want a record you can hand to an accountant.

How to invoice at a documented rate in 4 steps

How do I get today's billing rate?

import os
from apify_client import ApifyClient

client = ApifyClient(os.environ["APIFY_TOKEN"])
run = client.actor("thirdwatch/currency-rates-scraper").call(
    run_input={
        "baseCurrencies": ["USD"],
        "targetCurrencies": ["EUR", "INR"],
        "amount": 3000,
        "maxResults": 5,
    }
)
rate_rows = list(client.dataset(run["defaultDatasetId"]).iterate_items())

Set amount to the invoice value and converted_amount comes back precomputed — the number you put on the bill.

How do I backdate a rate for a late invoice?

Use date with the original invoice date:

run = client.actor("thirdwatch/currency-rates-scraper").call(
    run_input={
        "baseCurrencies": ["USD"],
        "targetCurrencies": ["EUR"],
        "date": "2026-08-31",
        "amount": 3000,
    }
)

You get the published fix for that day — the same number you would have used had you billed on time.

How do I store the audit trail?

Persist each record next to the invoice it priced:

import json, pathlib

store = pathlib.Path("fx_records.jsonl")
with store.open("a") as f:
    for r in rate_rows:
        f.write(json.dumps({"invoice": "INV-2041", **r}) + "\n")

One JSONL line per invoice carries pair, rate, date, and provider — everything an accountant or a disputed payment needs.

How do I watch for rate swings between quote and payment?

Schedule a daily run and compare to the quote-day rate:

quoted = 0.92  # USD/EUR at quote time
now = next(r["rate"] for r in rate_rows if r["pair"] == "USD/EUR")
if abs(now - quoted) / quoted > 0.02:
    print("Rate moved >2% since quote — flag the pending invoice")

A two-percent band is a reasonable nudge threshold for service invoicing.

Sample output

{"base_currency": "USD", "quote_currency": "EUR", "pair": "USD/EUR",
 "date": "2026-09-11", "rate": 0.9304, "inverse_rate": 1.0748,
 "amount": 3000, "converted_amount": 2791.2,
 "provider": "erapi", "provider_name": "ExchangeRate-API open access"}

date and provider_name are the audit fields — they make the number defensible months later.

Common pitfalls

Free sources publish once daily, so a same-day rate is a fix, not a tick — fine for invoicing, wrong for trading. Weekend invoices resolve to the nearest published day; state the convention in your terms. Payment processors apply their own spread on top of the mid-market rate — your documented rate is the benchmark, not the received amount. The actor names the provider per record so your audit trail survives a source change.

Related use cases

• Track exchange rates for international pricing
• Build a historical FX rate dataset
• Guide to scraping business data
• Blog hub