Introduction

This backend api serves combined order books and arbitrage opportunity data (overlapping bid / ask orders) for specified base-quote symbol pairs from the following exchanges:

• Bittrex
• Poloniex
• Kraken
• Binance
• Hitbtc

It offers the ability to choose from ETH or BTC as the base symbol to be paired with large number of possible quote symbols. ETH-BTC is the default pair if none are specified.

Setup

1. Install Node js 8 or higher

2. Run npm install from the project root

Running the server

1. Run npm start from the project root.

Running tests

1. Run npm test from the project root

Note that the backend server cannot be running while tests are running so that listening ports do not conflict.

Notes

Price Precision

Most exchanges offer 8 decimal places of precision, making it very rare that orders from multiple order books fall on the same price and be combined.

For this reason calls to the /combined include a precision parameter. The allows the frontend to see how different precisions effect how ordersd are combined across order books from different exchanges.

Extensibility

Designed with extensibility in mind. New exchanges can be added via the following steps:

• Extend src/exchanges/BaseExchange.js
• Populate symbolTransationList as needed. Poloniex is used as the symbol standard.
• Implement getNormalizedOrderBook() to return data in the same format as existing exchanges