diff --git a/bot/index.js b/bot/index.js
index f482844..6128ff2 100644
--- a/bot/index.js
+++ b/bot/index.js
@@ -79,9 +79,9 @@ const getAmount = function (req) {
 
         Promise.all([labelPromise, tokenPricePromise])
             .then(function (values) {
-                let label = values[0]
-                let tokenPrice = values[1]
-                let amountToPayDollar = config.priceHour * config.bountyLabels[label.name]
+                const label = values[0]
+                const tokenPrice = values[1]
+                const amountToPayDollar = config.priceHour * config.bountyLabels[label.name]
                 resolve(amountToPayDollar / tokenPrice)
             })
             .catch((err) => {
@@ -112,8 +112,8 @@ const error = function (errorMessage) {
 
 
 const sendTransaction = async function (to, amount, gasPrice) {
-    var chainId = providers.Provider.chainId.ropsten
-    var chainName = providers.networks.ropsten
+    let chainId = providers.Provider.chainId.ropsten
+    let chainName = providers.networks.ropsten
 
     if (config.realTransaction) {
         chainId = providers.Provider.chainId.homestead
diff --git a/bot/prices.js b/bot/prices.js
index 63cc7f6..c938336 100644
--- a/bot/prices.js
+++ b/bot/prices.js
@@ -22,8 +22,8 @@ const getGasPrice = function () {
             // we are done, resolve promise with those joined chunks
             response.on('end', () => {
                 // safeLowWait returns GWei (10^10 Wei).
-                let jsonBody = JSON.parse(body.join(''))
-                let gasPriceWei = parseInt(jsonBody['safeLowWait']) * Math.pow(10, 10)
+                const jsonBody = JSON.parse(body.join(''))
+                const gasPriceWei = parseInt(jsonBody['safeLowWait']) * Math.pow(10, 10)
                 resolve(gasPriceWei)
             })
         })
@@ -57,8 +57,8 @@ const getTokenPrice = function (token) {
             response.on('data', (chunk) => body.push(chunk))
             // we are done, resolve promise with those joined chunks
             response.on('end', () => {
-                let jsonBody = JSON.parse(body.join(''))
-                let tokenPrice = parseFloat(jsonBody[currency])
+                const jsonBody = JSON.parse(body.join(''))
+                const tokenPrice = parseFloat(jsonBody[currency])
                 resolve(tokenPrice)
             })
         })
diff --git a/config/index.js b/config/index.js
index 03ad5f2..94567eb 100644
--- a/config/index.js
+++ b/config/index.js
@@ -1,4 +1,4 @@
-var _ = require("lodash")
-var defaults = require("./default.js")
-var config = require("./" + (process.env.NODE_ENV || "default") + ".js")
+const _ = require("lodash")
+const defaults = require("./default.js")
+const config = require("./" + (process.env.NODE_ENV || "default") + ".js")
 module.exports = _.merge({}, defaults, config)
diff --git a/index.js b/index.js
index 255d4f2..2215922 100644
--- a/index.js
+++ b/index.js
@@ -12,12 +12,12 @@ const bot = require('./bot')
 const crypto = require('crypto')
 
 
-var express = require('express'),
-    cors = require('cors'),
-    helmet = require('helmet'),
-    app = express(),
-    bodyParser = require('body-parser'),
-    jsonParser = bodyParser.json()
+const express = require('express'),
+      cors = require('cors'),
+      helmet = require('helmet'),
+      app = express(),
+      bodyParser = require('body-parser'),
+      jsonParser = bodyParser.json()
 
 app.use(cors())
 app.use(helmet())
diff --git a/test/test_bot.js b/test/test_bot.js
index a9d0583..c16b1f2 100644
--- a/test/test_bot.js
+++ b/test/test_bot.js
@@ -7,10 +7,10 @@ const bot = require('../bot')
 
 
 // status-open-bounty comment from https://github.com/status-im/autobounty/issues/1
-let sob_comment = 'Current balance: 0.000000 ETH\nTokens: SNT: 2500.00 ANT: 25.00\nContract address: 0x3645fe42b1a744ad98cc032c22472388806f86f9\nNetwork: Mainnet\n To claim this bounty sign up at https://openbounty.status.im and make sure to update your Ethereum address in My Payment Details so that the bounty is correctly allocated.\nTo fund it, send ETH or ERC20/ERC223 tokens to the contract address.'
+const sob_comment = 'Current balance: 0.000000 ETH\nTokens: SNT: 2500.00 ANT: 25.00\nContract address: 0x3645fe42b1a744ad98cc032c22472388806f86f9\nNetwork: Mainnet\n To claim this bounty sign up at https://openbounty.status.im and make sure to update your Ethereum address in My Payment Details so that the bounty is correctly allocated.\nTo fund it, send ETH or ERC20/ERC223 tokens to the contract address.'
 
 // Fake requests
-let requests = [
+const requests = [
     { body: { action: 'created', comment: { body: 'Creating my first comment', user: { login: 'randomUser' } } } },
     { body: { action: 'edited', comment: { body: 'Editing my comment', user: { login: 'RandomUser' } } } },
     { body: { action: 'edited', comment: { body: sob_comment, user: { login: 'status-open-bounty' } } } },
@@ -43,9 +43,9 @@ describe('Bot behavior', function () {
         it('should return the amount for the issue given the price per hour and the bounty label for this issue', (done) => {
             bot.getAmount(requests[3])
                 .then(function (amount) {
-                    let label = 'bounty-s'
-                    let tokenPrice = 0.35
-                    let priceInDollars = config.priceHour * config.bountyLabels[label]
+                    const label = 'bounty-s'
+                    const tokenPrice = 0.35
+                    const priceInDollars = config.priceHour * config.bountyLabels[label]
                     expected_amount = priceInDollars / tokenPrice
                     assert.equal(amount, expected_amount)
                     done()