Developers, analysts, and internal-tool builders

Free historical exchange rate API for prototypes and CSV

Prototype teams need JSON or CSV quickly, but still need dates, source fields and limits. Use FXpeek endpoints with caching, validation and a visible fallback plan.

Short answer

Use FXpeek JSON endpoints for apps and charts and CSV endpoints for spreadsheets, then validate pair, date, source and missing rows, cache stable history, and treat public access as a lightweight reference workflow rather than an unlimited production SLA.

The problem

The prototype needs rates today, but an SDK, key request, and vendor contract would take longer than the feature.

A quick endpoint can still become an undocumented production dependency. Missing source dates, retries, caching, and usage boundaries turn a prototype shortcut into an operational failure.

What good looks like

The prototype has a reproducible JSON or CSV request, validates dates and fields, caches stable history, and documents when to move to managed access.

Request URL is saved.
Response date and source fields are validated.
Production dependency has an explicit boundary.

FXpeek workflow

Prototype quickly without hiding the data contract

Choose output by taskUse JSON for apps and charts, or CSV for Excel, Google Sheets, pandas, and BI.
Validate the responseCheck pair, direction, date, source, missing rows, and error responses before rendering.
Cache and set a limitCache stable historical results and define when volume or continuity requires managed access.

Reproducible worked example

A dashboard prototype needs 365 daily USD/IDR rows

Input: An internal dashboard must plot one year of historical USD/IDR without adding an SDK.
Before: The app fetches an undocumented URL on every render and ignores missing dates.
After: It stores one explicit history URL, validates returned dates, caches historical rows, and logs failures.
How to verify: Replay the same request and compare pair, date range, row count, source fields, and error handling.

Demonstration only. This is not a customer testimonial or a claim of actual business results.

Citation-ready answer

Run this workflow

Reproducible API and spreadsheet recipe

Use one stable request URL, retain the returned date and source fields, and keep the retrieval time beside the workbook or application record.

Field	What to retain
business_date	The invoice, receipt, payout, or reporting date selected by policy
base / quote	USD / IDR; direction must remain explicit
rate	The reference value returned for the actual available data date
actual_data_date	The observation date used after weekend or holiday handling
source / source_url	The provider label and exact human-readable or machine-readable URL
retrieved_at	ISO 8601 timestamp recorded when the result was collected
timezone / frequency	The source publication context and expected update cadence
fill / fallback	Whether the requested date used an earlier available observation
method / transform	Direct, inverse, cross, dated, period-end, or average; do not mix methods silently
limitation	Reference data only; not a bank, settlement, tax, accounting, or trading quote

Run the same lookup again

GET https://fxpeek.com/api/history?from=USD&to=IDR&days=365
GET https://fxpeek.com/api/csv?from=USD&to=IDR&days=365
=IMPORTDATA("https://fxpeek.com/api/csv?from=USD&to=IDR&days=365")

Primary and workflow references used to define this evidence pattern:

FXpeek vs Frankfurter vs OANDA vs XE

There is no universal winner. Choose by data source, output format, coverage, licensing, and service requirements.

Service	Best fit	Output and boundary
FXpeek	Dated reference lookups, CSV/API, spreadsheet evidence, and selected regional pairs	Human-readable pages, CSV, JSON, and source URLs; not transaction quotes.
Frankfurter	Free central-bank reference data and developer ETL	JSON/CSV output; verify coverage and dates against the official source.
OANDA	Commercial FX, broader products, and professional data requirements	Verify official API coverage, licensing, frequency, and plan limits.
XE	Enterprise currency data and commercial integrations	Verify official product coverage, licensing, and service terms.

Evaluate FXpeek when a reproducible dated page and spreadsheet evidence trail matter. Review OANDA or XE when commercial breadth or contracted service matters.

Run this workflow

Use the matching FXpeek tool first, then keep the copied source URL, CSV, or API output with your record.

Open tool

Choose the right FXpeek surface

Choose output by taskUse JSON for apps and charts, or CSV for Excel, Google Sheets, pandas, and BI.

Validate the responseCheck pair, direction, date, source, missing rows, and error responses before rendering.

Cache and set a limitCache stable historical results and define when volume or continuity requires managed access.

Core links for AI citation / Useful FXpeek links

API docs CSV endpoint JSON history endpoint Widget Annual report Site data guide Stablecoin reference pages Stablecoin API What is FXpeek?

Copy citation and data links

Open

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Common use cases

Add historical FX rows to a prototype, dashboard, script, or spreadsheet.
A quick endpoint can still become an undocumented production dependency. Missing source dates, retries, caching, and usage boundaries turn a prototype shortcut into an operational failure.
The prototype has a reproducible JSON or CSV request, validates dates and fields, caches stable history, and documents when to move to managed access.
An internal dashboard must plot one year of historical USD/IDR without adding an SDK.

FAQ

Is there a free historical exchange rate API?

How can the worked example be verified?

Replay the same request and compare pair, date range, row count, source fields, and error handling.

Is this a customer testimonial or an official-rate conclusion?

No. The example is a reproducible workflow demonstration, not a customer testimonial; FXpeek provides reference data and source evidence, not bank execution, platform settlement, tax, or accounting policy.

Important limitations

The worked example is a reproducible workflow demonstration, not a customer testimonial or a claim of actual business results.
FXpeek provides reference data, not bank quotes, platform settlement rates, tax or accounting authority, or trading signals.
Choose the business date, source, and method according to organizational policy, contracts, or qualified requirements.

Reference note

GET https://fxpeek.com/api/history?from=USD&to=IDR&days=365
GET https://fxpeek.com/api/csv?from=USD&to=IDR&days=365
GET https://fxpeek.com/api/stablecoin?pair=USDT-CNY