This project provides a simple user interface onto the GDAX getHistoricRates and getProducts endpoints.

With it, you can fetch the coin history for Bitcoin, Litecoin or Ethereum for any start and end date you wish. The app will then show the first and last ten entries returned from the GDAX API.

Installing the app

Clone this repo into a folder on your machine. Then enter:

npm install

Running the app

Run the app using:

npm run start

Then go to a browser window (if one hasn't already opened) and browse to http://localhost:3000

Running the Tests

To run the unit tests, enter:

npm run test

About the App

The app's purpose

The app has been written to help developers (and myself!) understand the GDAX getHistoricRates() endpoint, which can be a bit confusing, as it will only return a maximum of 200 candles for any one request. If there are more than 200 candles between your start and end times, the request will be rejected. When that happens, it's not clear how to change your request to get the API to return the data you want.

In order to make a successful request between two times, you must set a parameter called granularity, which specifies the time interval, in seconds, that should be used for each candle. By default, granularity is 1, meaning you will receive data corresponding to 1 candle per second between your start and end times.

If, however, your start and end times are more than 200 seconds apart, you must change the granularity parameter. For example, to get a set of 200 candles, each spaced 2 seconds apart, you'd use a granularity value of 2.

However, calculating the granularity for an arbitrary start and end time is where things get a bit tricky.

On the GDAX API page, there are no example requests showing you what value your granularity should be be between two points. Without this, should you receive an error, it is hard to tell whether you've entered an incorrectly-formatted start time, end time, or granularity value, as you get the same response in each case: a simple error.

Hence the need for this app.

The Coin History app calculates the granularity between any two dates for you automatically. Simply enter the start and end date, and the required granularity wil automatically appear. Hit Fetch Data, and the data will be retrieved, with the first 10 and last 10 data items displayed so you can see what the result of the API call is.

In addition, if you want to alter the format of the date for the returned data, simply enter a MomentJS-compatible date-format in the Date Format Input Box, and the date's format will change instantly (to try this out, enter DD-MM-YYYY and the date of each candle change format to a four-digit year format).