# Frankfurter

[![Deploy](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy?template=https://github.com/hakanensari/frankfurter)

Frankfurter is a free and open source API for current and historical foreign exchange rates. It tracks data published by the European Central Bank. Rates are updated around 4PM CET every working day.

A public instance runs on `https://frankfurter.app`. You can also self-host with Heroku or Docker.

## Examples

Get the current foreign exchange rates.

```http
GET /latest HTTP/1.1
```

Get historical rates for any day since 1999.

```http
GET /2000-01-03 HTTP/1.1
```

Get historical rates for a time period.

```http
GET /2010-01-01..2010-01-31 HTTP/1.1
```

Get historical rates for a time period up to the present.

```http
GET /2010-01-01.. HTTP/1.1
```

Rates quote against the Euro by default. Quote against a different currency.

```http
GET /latest?from=USD HTTP/1.1
```

Request specific exchange rates.

```http
GET /latest?to=USD,GBP HTTP/1.1
```

Convert a specific amount.

```http
GET /latest?amount=1000&from=GBP&to=USD HTTP/1.1
```

With a full list of currencies, time series grow large in size. For better performance, use the to parameter to reduce the response weight.

```http
GET /2016-01-01..2016-12-31?from=GBP&to=USD HTTP/1.1
```

Here we return the current GBP/USD currency pair with JavaScript.

```js
// Fetch and display GBP/USD
fetch('/latest?from=GBP&to=USD')
  .then(resp => resp.json())
  .then((data) => { alert(`GBPUSD = ${data.rates.USD}`); });
```

Cache data whenever possible.

## Deployment

To build locally, type

```bash
docker-compose up -d
```

Now you can access the API at `http://localhost:8080`.

In production, create a [`.env`](.env.example) file and run with

```bash
docker-compose -f docker-compose.yml -f docker-compose.prod.yml up -d
```

To update to a newer image, run

```bash
docker-compose -f docker-compose.yml -f docker-compose.prod.yml pull
```

Within a few minutes, you will access the API at `https://yourdomain.com/`.

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