One of the intended uses of our REST API is to create automated trading bots that interact with our markets and accounts.
While trading bots come in an almost endless variety, they all share similar API integration characteristics, and all perform the following common tasks:
retrieving market data (ticker, order book, etc.)
making trading decisions (based upon the market data, or indicators derived from the market data, or other possible criteria)
placing/cancelling orders
Our REST API provides all of the functionality needed to implement a full featured trading bot, but knowing how to combine the different aspects of our API can be difficult, hence the following trading bot code is provided as an example.
The example code implements an indicator based trading bot (specifically an 80/20 over bought/sold RSI, with trading decisions based upon a 1 minute slope change), and shows how to integrate the market data, decision making, and trading aspects of a trading bot successfully.
Example Code (Node.js)
The trading bot code is a single Node.js file and integrates directly with our API. All configuration (API key, currency pair, indicator, order type, leverage etc.) is contained within the code for ease of reference.
The example code can be viewed below and can also be downloaded.
Bash
const axios = require('axios');
const sleep = require('sleep-promise');
const crypto = require("crypto");
const fs = require("fs");
const main = async () => {
const api_key_public = ""; // public api key
const api_key_private = ""; // private api key
// Configure market/orders/trades
const trade_symbol = 'XXBTZUSD';
const trade_interval = 1; // OHLC interval in minutes
const trade_size = 0.0001; // trade volume in base currency
const trade_leverage = 2;
// Initial indicator/trade variables
let trade_direction = 0;
let sma_values = [0.0, 0.0, 0.0];
let api_data = "";
let make_trade = 0;
let jsonData = "";
try {
while (true) {
console.log("Retrieving OHLC data...");
try {
const baseDomain = "https://api.kraken.com";
const publicPath = "/0/public/OHLC";
const inputParameters = `pair=${trade_symbol}&interval=${trade_interval}`;
const apiEndpointFullURL = `${baseDomain}${publicPath}?${inputParameters}`;
await axios.get(apiEndpointFullURL)
.then((res) => {
jsonData = res;
})
.catch((error) => {
jsonData = error;
});
api_data = jsonData.data;
} catch (error) {
console.log('Failed' + error);
}
if (jsonData.data.error.length == 0) {
console.log("Done..");
} else {
console.log(api_data.error);
}
// Calculating SMA
console.log('Calculating SMA 20...');
let api_ohlc = api_data.result[trade_symbol];
let api_ohlc_length = api_ohlc.length - 1;
let sma_temp = 0.0;
for (let count = 0; count < 20; count++) {
sma_temp += parseFloat(api_ohlc[api_ohlc_length - count][4]);
}
sma_temp = sma_temp / 20;
// Update SMA values
sma_values[2] = sma_values[1];
sma_values[1] = sma_values[0];
sma_values[0] = sma_temp;
console.log(sma_values[2]);
console.log(sma_values[1]);
console.log(sma_values[0]);
if (sma_values[2] == 0) {
console.log("Waiting " + trade_interval * 60 + ' seconds');
await sleep(trade_interval * 60 * 1000);
continue;
} else {
console.log("SMA 20 values...." + sma_values[2] + "/" + sma_values[1] + "/" + sma_values[0]);
}
// Trading Decision (Change in slope of SMA)
console.log("Trading decision ......");
if (sma_values[0] > sma_values[1] && sma_values[1] < sma_values[2]) {
make_trade = 1;
console.log("Long");
} else if (sma_values[0] < sma_values[1] && sma_values[1] > sma_values[2]) {
make_trade = -1;
console.log("Short");
} else {
make_trade = 0;
console.log("No Trade");
}
// Place Order
if (make_trade != 0) {
console.log('Placing Order/trade....');
try {
const api_path = '/0/private/AddOrder';
const api_nonce = (Date.now() * 1000).toString();
const api_post = `nonce=${api_nonce}&pair=${trade_symbol}&type=${make_trade == 1 ? 'buy' : 'sell'}&ordertype=market&volume=${trade_direction == 0 ? trade_size : trade_size * 2}&leverage=${trade_leverage > 0 ? trade_leverage : 'none'}`;
const signature = CreateAuthenticationSignature(api_key_private, api_path, api_nonce, api_post);
const api_data = await QueryAddOrder(api_post, api_path, signature, api_key_public);
const final = api_data.error.length == 0 ? api_data.result : api_data.error;
console.log("Done");
console.log(final);
} catch (err) {
console.log(err);
}
}
// Wait until next OHLC interval
console.log("Waiting " + trade_interval * 60 + ' seconds');
await sleep(trade_interval * 60 * 1000);
}
} catch (err) {
console.log(err);
}
};
function CreateAuthenticationSignature(apiPrivateKey, api_path, nonce, apiPostBodyData) {
const apiPost = nonce + apiPostBodyData;
const secret = Buffer.from(apiPrivateKey, "base64");
const sha256 = crypto.createHash("sha256");
const hash256 = sha256.update(apiPost).digest("binary");
const hmac512 = crypto.createHmac("sha512", secret);
const signatureString = hmac512
.update(api_path + hash256, "binary")
.digest("base64");
return signatureString;
}
async function QueryAddOrder(api_post, api_path, signature, api_key_public) {
const baseDomain = "https://api.kraken.com";
const apiEndpointFullURL = `${baseDomain}${api_path}`;
console.log(apiEndpointFullURL);
const httpOptions = {
headers: {
"API-Key": api_key_public,
"API-Sign": signature
}
};
await axios.post(apiEndpointFullURL, api_post, httpOptions)
.then((res) => {
jsonData = res;
})
.catch((err) => {
jsonData = err;
});
return jsonData.data;
}
main();