diff --git a/server/controllers/api/v1/index.js b/server/controllers/api/v1/index.js
index b562bc2af..45f07ae1f 100644
--- a/server/controllers/api/v1/index.js
+++ b/server/controllers/api/v1/index.js
@@ -1,12 +1,12 @@
 'use strict'
 
-var express = require('express')
+const express = require('express')
 
-var router = express.Router()
+const router = express.Router()
 
-var podsController = require('./pods')
-var remoteVideosController = require('./remoteVideos')
-var videosController = require('./videos')
+const podsController = require('./pods')
+const remoteVideosController = require('./remoteVideos')
+const videosController = require('./videos')
 
 router.use('/pods', podsController)
 router.use('/remotevideos', remoteVideosController)
diff --git a/server/controllers/api/v1/pods.js b/server/controllers/api/v1/pods.js
index fa9832914..dbe1a7372 100644
--- a/server/controllers/api/v1/pods.js
+++ b/server/controllers/api/v1/pods.js
@@ -1,20 +1,20 @@
 'use strict'
 
-var express = require('express')
-var fs = require('fs')
+const express = require('express')
+const fs = require('fs')
 
-var logger = require('../../../helpers/logger')
-var friends = require('../../../lib/friends')
-var middleware = require('../../../middlewares')
-var cacheMiddleware = middleware.cache
-var peertubeCrypto = require('../../../helpers/peertubeCrypto')
-var Pods = require('../../../models/pods')
-var reqValidator = middleware.reqValidators.pods
-var secureMiddleware = middleware.secure
-var secureRequest = middleware.reqValidators.remote.secureRequest
-var Videos = require('../../../models/videos')
+const logger = require('../../../helpers/logger')
+const friends = require('../../../lib/friends')
+const middleware = require('../../../middlewares')
+const cacheMiddleware = middleware.cache
+const peertubeCrypto = require('../../../helpers/peertubeCrypto')
+const Pods = require('../../../models/pods')
+const reqValidator = middleware.reqValidators.pods
+const secureMiddleware = middleware.secure
+const secureRequest = middleware.reqValidators.remote.secureRequest
+const Videos = require('../../../models/videos')
 
-var router = express.Router()
+const router = express.Router()
 
 router.get('/', cacheMiddleware.cache(false), listPods)
 router.post('/', reqValidator.podsAdd, cacheMiddleware.cache(false), addPods)
@@ -30,7 +30,7 @@ module.exports = router
 // ---------------------------------------------------------------------------
 
 function addPods (req, res, next) {
-  var informations = req.body.data
+  const informations = req.body.data
   Pods.add(informations, function (err) {
     if (err) return next(err)
 
@@ -71,7 +71,7 @@ function makeFriends (req, res, next) {
 }
 
 function removePods (req, res, next) {
-  var url = req.body.signature.url
+  const url = req.body.signature.url
   Pods.remove(url, function (err) {
     if (err) return next(err)
 
diff --git a/server/controllers/api/v1/remoteVideos.js b/server/controllers/api/v1/remoteVideos.js
index 7622e39f5..58222de52 100644
--- a/server/controllers/api/v1/remoteVideos.js
+++ b/server/controllers/api/v1/remoteVideos.js
@@ -1,15 +1,15 @@
 'use strict'
 
-var express = require('express')
-var pluck = require('lodash-node/compat/collection/pluck')
+const express = require('express')
+const pluck = require('lodash-node/compat/collection/pluck')
 
-var middleware = require('../../../middlewares')
-var secureMiddleware = middleware.secure
-var cacheMiddleware = middleware.cache
-var reqValidator = middleware.reqValidators.remote
-var videos = require('../../../models/videos')
+const middleware = require('../../../middlewares')
+const secureMiddleware = middleware.secure
+const cacheMiddleware = middleware.cache
+const reqValidator = middleware.reqValidators.remote
+const videos = require('../../../models/videos')
 
-var router = express.Router()
+const router = express.Router()
 
 router.post('/add',
   reqValidator.secureRequest,
@@ -42,8 +42,8 @@ function addRemoteVideos (req, res, next) {
 }
 
 function removeRemoteVideo (req, res, next) {
-  var url = req.body.signature.url
-  var magnetUris = pluck(req.body.data, 'magnetUri')
+  const url = req.body.signature.url
+  const magnetUris = pluck(req.body.data, 'magnetUri')
 
   videos.removeRemotesOfByMagnetUris(url, magnetUris, function (err) {
     if (err) return next(err)
diff --git a/server/controllers/api/v1/videos.js b/server/controllers/api/v1/videos.js
index 76cad62d1..1eea417d4 100644
--- a/server/controllers/api/v1/videos.js
+++ b/server/controllers/api/v1/videos.js
@@ -1,41 +1,41 @@
 'use strict'
 
-var config = require('config')
-var crypto = require('crypto')
-var express = require('express')
-var multer = require('multer')
+const config = require('config')
+const crypto = require('crypto')
+const express = require('express')
+const multer = require('multer')
 
-var logger = require('../../../helpers/logger')
-var friends = require('../../../lib/friends')
-var middleware = require('../../../middlewares')
-var cacheMiddleware = middleware.cache
-var reqValidator = middleware.reqValidators.videos
-var Videos = require('../../../models/videos') // model
-var videos = require('../../../lib/videos')
-var webtorrent = require('../../../lib/webtorrent')
+const logger = require('../../../helpers/logger')
+const friends = require('../../../lib/friends')
+const middleware = require('../../../middlewares')
+const cacheMiddleware = middleware.cache
+const reqValidator = middleware.reqValidators.videos
+const Videos = require('../../../models/videos') // model
+const videos = require('../../../lib/videos')
+const webtorrent = require('../../../lib/webtorrent')
 
-var router = express.Router()
-var uploads = config.get('storage.uploads')
+const router = express.Router()
+const uploads = config.get('storage.uploads')
 
 // multer configuration
-var storage = multer.diskStorage({
+const storage = multer.diskStorage({
   destination: function (req, file, cb) {
     cb(null, uploads)
   },
 
   filename: function (req, file, cb) {
-    var extension = ''
+    let extension = ''
     if (file.mimetype === 'video/webm') extension = 'webm'
     else if (file.mimetype === 'video/mp4') extension = 'mp4'
     else if (file.mimetype === 'video/ogg') extension = 'ogv'
     crypto.pseudoRandomBytes(16, function (err, raw) {
-      var fieldname = err ? undefined : raw.toString('hex')
+      const fieldname = err ? undefined : raw.toString('hex')
       cb(null, fieldname + '.' + extension)
     })
   }
 })
 
-var reqFiles = multer({ storage: storage }).fields([{ name: 'input_video', maxCount: 1 }])
+const reqFiles = multer({ storage: storage }).fields([{ name: 'input_video', maxCount: 1 }])
 
 router.get('/', cacheMiddleware.cache(false), listVideos)
 router.post('/', reqFiles, reqValidator.videosAdd, cacheMiddleware.cache(false), addVideo)
@@ -50,8 +50,8 @@ module.exports = router
 // ---------------------------------------------------------------------------
 
 function addVideo (req, res, next) {
-  var video_file = req.files.input_video[0]
-  var video_infos = req.body
+  const video_file = req.files.input_video[0]
+  const video_infos = req.body
 
   videos.seed(video_file.path, function (err, torrent) {
     if (err) {
@@ -59,7 +59,7 @@ function addVideo (req, res, next) {
       return next(err)
     }
 
-    var video_data = {
+    const video_data = {
       name: video_infos.name,
       namePath: video_file.filename,
       description: video_infos.description,
@@ -103,7 +103,7 @@ function listVideos (req, res, next) {
 }
 
 function removeVideo (req, res, next) {
-  var video_id = req.params.id
+  const video_id = req.params.id
   Videos.get(video_id, function (err, video) {
     if (err) return next(err)
 
@@ -111,7 +111,7 @@ function removeVideo (req, res, next) {
       Videos.removeOwned(req.params.id, function (err) {
         if (err) return next(err)
 
-        var params = {
+        const params = {
           name: video.name,
           magnetUri: video.magnetUri
         }
diff --git a/server/controllers/index.js b/server/controllers/index.js
index 7b0288dbb..4c1d3dafe 100644
--- a/server/controllers/index.js
+++ b/server/controllers/index.js
@@ -1,8 +1,8 @@
 'use strict'
 
-var constants = require('../initializers/constants')
+const constants = require('../initializers/constants')
 
-var apiController = require('./api/' + constants.API_VERSION)
+const apiController = require('./api/' + constants.API_VERSION)
 
 module.exports = {
   api: apiController
diff --git a/server/helpers/customValidators.js b/server/helpers/customValidators.js
index 20c41f5da..a5ae32780 100644
--- a/server/helpers/customValidators.js
+++ b/server/helpers/customValidators.js
@@ -1,8 +1,8 @@
 'use strict'
 
-var validator = require('validator')
+const validator = require('validator')
 
-var customValidators = {
+const customValidators = {
   eachIsRemoteVideosAddValid: eachIsRemoteVideosAddValid,
   eachIsRemoteVideosRemoveValid: eachIsRemoteVideosRemoveValid,
   isArray: isArray
diff --git a/server/helpers/logger.js b/server/helpers/logger.js
index 1c15a0edd..d3fce4cc9 100644
--- a/server/helpers/logger.js
+++ b/server/helpers/logger.js
@@ -1,13 +1,13 @@
 // Thanks http://tostring.it/2014/06/23/advanced-logging-with-nodejs/
 'use strict'
 
-var config = require('config')
-var path = require('path')
-var winston = require('winston')
+const config = require('config')
+const path = require('path')
+const winston = require('winston')
 winston.emitErrs = true
 
-var logDir = path.join(__dirname, '..', '..', config.get('storage.logs'))
-var logger = new winston.Logger({
+const logDir = path.join(__dirname, '..', '..', config.get('storage.logs'))
+const logger = new winston.Logger({
   transports: [
     new winston.transports.File({
       level: 'debug',
diff --git a/server/helpers/peertubeCrypto.js b/server/helpers/peertubeCrypto.js
index 7e65c43e1..3826ebaf6 100644
--- a/server/helpers/peertubeCrypto.js
+++ b/server/helpers/peertubeCrypto.js
@@ -1,18 +1,18 @@
 'use strict'
 
-var config = require('config')
-var crypto = require('crypto')
-var fs = require('fs')
-var openssl = require('openssl-wrapper')
-var path = require('path')
-var ursa = require('ursa')
+const config = require('config')
+const crypto = require('crypto')
+const fs = require('fs')
+const openssl = require('openssl-wrapper')
+const path = require('path')
+const ursa = require('ursa')
 
-var logger = require('./logger')
+const logger = require('./logger')
 
-var certDir = path.join(__dirname, '..', '..', config.get('storage.certs'))
-var algorithm = 'aes-256-ctr'
+const certDir = path.join(__dirname, '..', '..', config.get('storage.certs'))
+const algorithm = 'aes-256-ctr'
 
-var peertubeCrypto = {
+const peertubeCrypto = {
   checkSignature: checkSignature,
   createCertsIfNotExist: createCertsIfNotExist,
   decrypt: decrypt,
@@ -22,8 +22,8 @@ var peertubeCrypto = {
 }
 
 function checkSignature (public_key, raw_data, hex_signature) {
-  var crt = ursa.createPublicKey(public_key)
-  var is_valid = crt.hashAndVerify('sha256', new Buffer(raw_data).toString('hex'), hex_signature, 'hex')
+  const crt = ursa.createPublicKey(public_key)
+  const is_valid = crt.hashAndVerify('sha256', new Buffer(raw_data).toString('hex'), hex_signature, 'hex')
   return is_valid
 }
 
@@ -43,22 +43,22 @@ function decrypt (key, data, callback) {
   fs.readFile(getCertDir() + 'peertube.key.pem', function (err, file) {
     if (err) return callback(err)
 
-    var my_private_key = ursa.createPrivateKey(file)
-    var decrypted_key = my_private_key.decrypt(key, 'hex', 'utf8')
-    var decrypted_data = symetricDecrypt(data, decrypted_key)
+    const my_private_key = ursa.createPrivateKey(file)
+    const decrypted_key = my_private_key.decrypt(key, 'hex', 'utf8')
+    const decrypted_data = symetricDecrypt(data, decrypted_key)
 
     return callback(null, decrypted_data)
   })
 }
 
 function encrypt (public_key, data, callback) {
-  var crt = ursa.createPublicKey(public_key)
+  const crt = ursa.createPublicKey(public_key)
 
   symetricEncrypt(data, function (err, dataEncrypted) {
     if (err) return callback(err)
 
-    var key = crt.encrypt(dataEncrypted.password, 'utf8', 'hex')
-    var encrypted = {
+    const key = crt.encrypt(dataEncrypted.password, 'utf8', 'hex')
+    const encrypted = {
       data: dataEncrypted.crypted,
       key: key
     }
@@ -72,8 +72,8 @@ function getCertDir () {
 }
 
 function sign (data) {
-  var myKey = ursa.createPrivateKey(fs.readFileSync(certDir + 'peertube.key.pem'))
-  var signature = myKey.hashAndSign('sha256', data, 'utf8', 'hex')
+  const myKey = ursa.createPrivateKey(fs.readFileSync(certDir + 'peertube.key.pem'))
+  const signature = myKey.hashAndSign('sha256', data, 'utf8', 'hex')
 
   return signature
 }
@@ -93,7 +93,7 @@ function certsExist (callback) {
 function createCerts (callback) {
   certsExist(function (exist) {
     if (exist === true) {
-      var string = 'Certs already exist.'
+      const string = 'Certs already exist.'
       logger.warning(string)
       return callback(new Error(string))
     }
@@ -129,8 +129,8 @@ function generatePassword (callback) {
 }
 
 function symetricDecrypt (text, password) {
-  var decipher = crypto.createDecipher(algorithm, password)
-  var dec = decipher.update(text, 'hex', 'utf8')
+  const decipher = crypto.createDecipher(algorithm, password)
+  let dec = decipher.update(text, 'hex', 'utf8')
   dec += decipher.final('utf8')
   return dec
 }
@@ -139,8 +139,8 @@ function symetricEncrypt (text, callback) {
   generatePassword(function (err, password) {
     if (err) return callback(err)
 
-    var cipher = crypto.createCipher(algorithm, password)
-    var crypted = cipher.update(text, 'utf8', 'hex')
+    const cipher = crypto.createCipher(algorithm, password)
+    let crypted = cipher.update(text, 'utf8', 'hex')
     crypted += cipher.final('hex')
     callback(null, { crypted: crypted, password: password })
   })
diff --git a/server/helpers/requests.js b/server/helpers/requests.js
index e19afa5ca..17b1127c0 100644
--- a/server/helpers/requests.js
+++ b/server/helpers/requests.js
@@ -1,19 +1,19 @@
 'use strict'
 
-var async = require('async')
-var config = require('config')
-var request = require('request')
-var replay = require('request-replay')
+const async = require('async')
+const config = require('config')
+const request = require('request')
+const replay = require('request-replay')
 
-var constants = require('../initializers/constants')
-var logger = require('./logger')
-var peertubeCrypto = require('./peertubeCrypto')
+const constants = require('../initializers/constants')
+const logger = require('./logger')
+const peertubeCrypto = require('./peertubeCrypto')
 
-var http = config.get('webserver.https') ? 'https' : 'http'
-var host = config.get('webserver.host')
-var port = config.get('webserver.port')
+const http = config.get('webserver.https') ? 'https' : 'http'
+const host = config.get('webserver.host')
+const port = config.get('webserver.port')
 
-var requests = {
+const requests = {
   makeMultipleRetryRequest: makeMultipleRetryRequest
 }
 
@@ -23,8 +23,8 @@ function makeMultipleRetryRequest (all_data, pods, callbackEach, callback) {
     callbackEach = null
   }
 
-  var url = http + '://' + host + ':' + port
-  var signature
+  const url = http + '://' + host + ':' + port
+  let signature
 
   // Add signature if it is specified in the params
   if (all_data.method === 'POST' && all_data.data && all_data.sign === true) {
@@ -43,7 +43,7 @@ function makeMultipleRetryRequest (all_data, pods, callbackEach, callback) {
       }
     }
 
-    var params = {
+    const params = {
       url: pod.url + all_data.path,
       method: all_data.method
     }
@@ -52,19 +52,16 @@ function makeMultipleRetryRequest (all_data, pods, callbackEach, callback) {
     if (all_data.method === 'POST' && all_data.data) {
       // Encrypt data ?
       if (all_data.encrypt === true) {
-        // TODO: ES6 with let
-        ;(function (copy_params, copy_url, copy_pod, copy_signature) {
-          peertubeCrypto.encrypt(pod.publicKey, JSON.stringify(all_data.data), function (err, encrypted) {
-            if (err) return callback(err)
+        peertubeCrypto.encrypt(pod.publicKey, JSON.stringify(all_data.data), function (err, encrypted) {
+          if (err) return callback(err)
 
-            copy_params.json = {
-              data: encrypted.data,
-              key: encrypted.key
-            }
+          params.json = {
+            data: encrypted.data,
+            key: encrypted.key
+          }
 
-            makeRetryRequest(copy_params, copy_url, copy_pod, copy_signature, callbackEachRetryRequest)
-          })
-        })(params, url, pod, signature)
+          makeRetryRequest(params, url, pod, signature, callbackEachRetryRequest)
+        })
       } else {
         params.json = { data: all_data.data }
         makeRetryRequest(params, url, pod, signature, callbackEachRetryRequest)
diff --git a/server/helpers/utils.js b/server/helpers/utils.js
index d2c9ad8b2..1f7839673 100644
--- a/server/helpers/utils.js
+++ b/server/helpers/utils.js
@@ -1,8 +1,8 @@
 'use strict'
 
-var logger = require('./logger')
+const logger = require('./logger')
 
-var utils = {
+const utils = {
   cleanForExit: cleanForExit
 }
 
diff --git a/server/initializers/checker.js b/server/initializers/checker.js
index 44d9ea85b..a21e54982 100644
--- a/server/initializers/checker.js
+++ b/server/initializers/checker.js
@@ -1,24 +1,24 @@
 'use strict'
 
-var config = require('config')
-var mkdirp = require('mkdirp')
-var path = require('path')
+const config = require('config')
+const mkdirp = require('mkdirp')
+const path = require('path')
 
-var checker = {
+const checker = {
   checkConfig: checkConfig,
   createDirectoriesIfNotExist: createDirectoriesIfNotExist
 }
 
 // Check the config files
 function checkConfig () {
-  var required = [ 'listen.port',
+  const required = [ 'listen.port',
     'webserver.https', 'webserver.host', 'webserver.port',
     'database.host', 'database.port', 'database.suffix',
     'storage.certs', 'storage.uploads', 'storage.logs',
     'network.friends' ]
-  var miss = []
+  const miss = []
 
-  for (var key of required) {
+  for (const key of required) {
     if (!config.has(key)) {
       miss.push(key)
     }
@@ -29,10 +29,10 @@ function checkConfig () {
 
 // Create directories for the storage if it doesn't exist
 function createDirectoriesIfNotExist () {
-  var storages = config.get('storage')
+  const storages = config.get('storage')
 
-  for (var key of Object.keys(storages)) {
-    var dir = storages[key]
+  for (const key of Object.keys(storages)) {
+    const dir = storages[key]
     try {
       mkdirp.sync(path.join(__dirname, '..', '..', dir))
     } catch (error) {
diff --git a/server/initializers/constants.js b/server/initializers/constants.js
index 16e50443b..dc08805b9 100644
--- a/server/initializers/constants.js
+++ b/server/initializers/constants.js
@@ -1,22 +1,22 @@
 'use strict'
 
 // API version of our pod
-var API_VERSION = 'v1'
+const API_VERSION = 'v1'
 
 // Score a pod has when we create it as a friend
-var FRIEND_BASE_SCORE = 100
+let FRIEND_BASE_SCORE = 100
 
 // Time to wait between requests to the friends
-var INTERVAL = 60000
+let INTERVAL = 60000
 
 // Number of points we add/remove from a friend after a successful/bad request
-var PODS_SCORE = {
+const PODS_SCORE = {
   MALUS: -10,
   BONUS: 10
 }
 
 // Number of retries we make for the make retry requests (to friends...)
-var REQUEST_RETRIES = 10
+let REQUEST_RETRIES = 10
 
 // Special constants for a test instance
 if (isTestInstance() === true) {
diff --git a/server/initializers/database.js b/server/initializers/database.js
index a917442ec..830cc7dd8 100644
--- a/server/initializers/database.js
+++ b/server/initializers/database.js
@@ -1,15 +1,15 @@
 'use strict'
 
-var config = require('config')
-var mongoose = require('mongoose')
+const config = require('config')
+const mongoose = require('mongoose')
 
-var logger = require('../helpers/logger')
+const logger = require('../helpers/logger')
 
-var dbname = 'peertube' + config.get('database.suffix')
-var host = config.get('database.host')
-var port = config.get('database.port')
+const dbname = 'peertube' + config.get('database.suffix')
+const host = config.get('database.host')
+const port = config.get('database.port')
 
-var database = {
+const database = {
   connect: connect
 }
 
diff --git a/server/lib/friends.js b/server/lib/friends.js
index 006a64404..c3c231604 100644
--- a/server/lib/friends.js
+++ b/server/lib/friends.js
@@ -1,23 +1,23 @@
 'use strict'
 
-var async = require('async')
-var config = require('config')
-var fs = require('fs')
-var request = require('request')
+const async = require('async')
+const config = require('config')
+const fs = require('fs')
+const request = require('request')
 
-var constants = require('../initializers/constants')
-var logger = require('../helpers/logger')
-var peertubeCrypto = require('../helpers/peertubeCrypto')
-var Pods = require('../models/pods')
-var poolRequests = require('../lib/poolRequests')
-var requests = require('../helpers/requests')
-var Videos = require('../models/videos')
+const constants = require('../initializers/constants')
+const logger = require('../helpers/logger')
+const peertubeCrypto = require('../helpers/peertubeCrypto')
+const Pods = require('../models/pods')
+const poolRequests = require('../lib/poolRequests')
+const requests = require('../helpers/requests')
+const Videos = require('../models/videos')
 
-var http = config.get('webserver.https') ? 'https' : 'http'
-var host = config.get('webserver.host')
-var port = config.get('webserver.port')
+const http = config.get('webserver.https') ? 'https' : 'http'
+const host = config.get('webserver.host')
+const port = config.get('webserver.port')
 
-var pods = {
+const pods = {
   addVideoToFriends: addVideoToFriends,
   hasFriends: hasFriends,
   makeFriends: makeFriends,
@@ -27,7 +27,7 @@ var pods = {
 
 function addVideoToFriends (video) {
   // To avoid duplicates
-  var id = video.name + video.magnetUri
+  const id = video.name + video.magnetUri
   // ensure namePath is null
   video.namePath = null
   poolRequests.addRequest(id, 'add', video)
@@ -37,13 +37,13 @@ function hasFriends (callback) {
   Pods.count(function (err, count) {
     if (err) return callback(err)
 
-    var has_friends = (count !== 0)
+    const has_friends = (count !== 0)
     callback(null, has_friends)
   })
 }
 
 function makeFriends (callback) {
-  var pods_score = {}
+  const pods_score = {}
 
   logger.info('Make friends!')
   fs.readFile(peertubeCrypto.getCertDir() + 'peertube.pub', 'utf8', function (err, cert) {
@@ -52,7 +52,7 @@ function makeFriends (callback) {
       return callback(err)
     }
 
-    var urls = config.get('network.friends')
+    const urls = config.get('network.friends')
 
     async.each(urls, function (url, callback) {
       computeForeignPodsList(url, pods_score, callback)
@@ -60,8 +60,8 @@ function makeFriends (callback) {
       if (err) return callback(err)
 
       logger.debug('Pods scores computed.', { pods_score: pods_score })
-      var pods_list = computeWinningPods(urls, pods_score)
-      logger.debug('Pods that we keep computed.', { pods_to_keep: pods_list })
+      const pods_list = computeWinningPods(urls, pods_score)
+      logger.debug('Pods that we keep.', { pods_to_keep: pods_list })
 
       makeRequestsToWinningPods(cert, pods_list, callback)
     })
@@ -77,7 +77,7 @@ function quitFriends (callback) {
   Pods.list(function (err, pods) {
     if (err) return callback(err)
 
-    var request = {
+    const request = {
       method: 'POST',
       path: '/api/' + constants.API_VERSION + '/pods/remove',
       sign: true,
@@ -109,7 +109,7 @@ function quitFriends (callback) {
 
 function removeVideoToFriends (video) {
   // To avoid duplicates
-  var id = video.name + video.magnetUri
+  const id = video.name + video.magnetUri
   poolRequests.addRequest(id, 'remove', video)
 }
 
@@ -128,7 +128,7 @@ function computeForeignPodsList (url, pods_score, callback) {
     if (foreign_pods_list.length === 0) return callback()
 
     async.each(foreign_pods_list, function (foreign_pod, callback_each) {
-      var foreign_url = foreign_pod.url
+      const foreign_url = foreign_pod.url
 
       if (pods_score[foreign_url]) pods_score[foreign_url]++
       else pods_score[foreign_url] = 1
@@ -143,8 +143,8 @@ function computeForeignPodsList (url, pods_score, callback) {
 function computeWinningPods (urls, pods_score) {
   // Build the list of pods to add
   // Only add a pod if it exists in more than a half base pods
-  var pods_list = []
-  var base_score = urls.length / 2
+  const pods_list = []
+  const base_score = urls.length / 2
   Object.keys(pods_score).forEach(function (pod) {
     if (pods_score[pod] > base_score) pods_list.push({ url: pod })
   })
@@ -153,7 +153,7 @@ function computeWinningPods (urls, pods_score) {
 }
 
 function getForeignPodsList (url, callback) {
-  var path = '/api/' + constants.API_VERSION + '/pods'
+  const path = '/api/' + constants.API_VERSION + '/pods'
 
   request.get(url + path, function (err, response, body) {
     if (err) return callback(err)
@@ -175,7 +175,7 @@ function makeRequestsToWinningPods (cert, pods_list, callback) {
       return callback(err)
     }
 
-    var data = {
+    const data = {
       url: http + '://' + host + ':' + port,
       publicKey: cert,
       videos: videos_list
diff --git a/server/lib/poolRequests.js b/server/lib/poolRequests.js
index f786c3c7a..2eb501311 100644
--- a/server/lib/poolRequests.js
+++ b/server/lib/poolRequests.js
@@ -1,18 +1,18 @@
 'use strict'
 
-var async = require('async')
-var pluck = require('lodash-node/compat/collection/pluck')
+const async = require('async')
+const pluck = require('lodash-node/compat/collection/pluck')
 
-var constants = require('../initializers/constants')
-var logger = require('../helpers/logger')
-var Pods = require('../models/pods')
-var PoolRequests = require('../models/poolRequests')
-var requests = require('../helpers/requests')
-var Videos = require('../models/videos')
+const constants = require('../initializers/constants')
+const logger = require('../helpers/logger')
+const Pods = require('../models/pods')
+const PoolRequests = require('../models/poolRequests')
+const requests = require('../helpers/requests')
+const Videos = require('../models/videos')
 
-var timer = null
+let timer = null
 
-var poolRequests = {
+const poolRequests = {
   activate: activate,
   addRequest: addRequest,
   deactivate: deactivate,
@@ -77,7 +77,7 @@ function makePoolRequest (type, requests_to_make, callback) {
   Pods.list(function (err, pods) {
     if (err) return callback(err)
 
-    var params = {
+    const params = {
       encrypt: true,
       sign: true,
       method: 'POST',
@@ -93,8 +93,8 @@ function makePoolRequest (type, requests_to_make, callback) {
       return callback(new Error('Unkown pool request type.'))
     }
 
-    var bad_pods = []
-    var good_pods = []
+    const bad_pods = []
+    const good_pods = []
 
     requests.makeMultipleRetryRequest(params, pods, callbackEachPodFinished, callbackAllPodsFinished)
 
@@ -129,7 +129,7 @@ function makePoolRequests () {
 
     if (pool_requests.length === 0) return
 
-    var requests_to_make = {
+    const requests_to_make = {
       add: {
         ids: [],
         requests: []
@@ -184,14 +184,14 @@ function removeBadPods () {
 
     if (pods.length === 0) return
 
-    var urls = pluck(pods, 'url')
-    var ids = pluck(pods, '_id')
+    const urls = pluck(pods, 'url')
+    const ids = pluck(pods, '_id')
 
     Videos.removeAllRemotesOf(urls, function (err, r) {
       if (err) {
         logger.error('Cannot remove videos from a pod that we removing.', { error: err })
       } else {
-        var videos_removed = r.result.n
+        const videos_removed = r.result.n
         logger.info('Removed %d videos.', videos_removed)
       }
 
@@ -199,7 +199,7 @@ function removeBadPods () {
         if (err) {
           logger.error('Cannot remove bad pods.', { error: err })
         } else {
-          var pods_removed = r.result.n
+          const pods_removed = r.result.n
           logger.info('Removed %d pods.', pods_removed)
         }
       })
diff --git a/server/lib/videos.js b/server/lib/videos.js
index a5fe7b0c4..eb3a0125a 100644
--- a/server/lib/videos.js
+++ b/server/lib/videos.js
@@ -1,25 +1,24 @@
 'use strict'
 
-var async = require('async')
-var config = require('config')
-// TODO
-var path = require('path')
-var webtorrent = require('../lib/webtorrent')
+const async = require('async')
+const config = require('config')
+const pathUtils = require('path')
+const webtorrent = require('../lib/webtorrent')
 
-var logger = require('../helpers/logger')
-var Videos = require('../models/videos')
+const logger = require('../helpers/logger')
+const Videos = require('../models/videos')
 
-var uploadDir = path.join(__dirname, '..', '..', config.get('storage.uploads'))
+const uploadDir = pathUtils.join(__dirname, '..', '..', config.get('storage.uploads'))
 
-var videos = {
+const videos = {
   getVideoState: getVideoState,
   seed: seed,
   seedAllExisting: seedAllExisting
 }
 
 function getVideoState (video, callback) {
-  var exist = (video !== null)
-  var owned = false
+  const exist = (video !== null)
+  let owned = false
   if (exist === true) {
     owned = (video.namePath !== null)
   }
diff --git a/server/lib/webtorrent.js b/server/lib/webtorrent.js
index cb641fead..455b086a3 100644
--- a/server/lib/webtorrent.js
+++ b/server/lib/webtorrent.js
@@ -1,20 +1,20 @@
 'use strict'
 
-var config = require('config')
-var ipc = require('node-ipc')
-var pathUtils = require('path')
-var spawn = require('electron-spawn')
+const config = require('config')
+const ipc = require('node-ipc')
+const pathUtils = require('path')
+const spawn = require('electron-spawn')
 
-var logger = require('../helpers/logger')
+const logger = require('../helpers/logger')
 
-var host = config.get('webserver.host')
-var port = config.get('webserver.port')
-var nodeKey = 'webtorrentnode' + port
-var processKey = 'webtorrentprocess' + port
+let host = config.get('webserver.host')
+let port = config.get('webserver.port')
+let nodeKey = 'webtorrentnode' + port
+let processKey = 'webtorrentprocess' + port
 ipc.config.silent = true
 ipc.config.id = nodeKey
 
-var webtorrent = {
+const webtorrent = {
   add: add,
   app: null, // Pid of the app
   create: create,
@@ -42,7 +42,7 @@ function create (options, callback) {
     if (!webtorrent.silent) logger.info('IPC server ready.')
 
     // Run a timeout of 30s after which we exit the process
-    var timeout_webtorrent_process = setTimeout(function () {
+    const timeout_webtorrent_process = setTimeout(function () {
       throw new Error('Timeout : cannot run the webtorrent process. Please ensure you have electron-prebuilt npm package installed with xvfb-run.')
     }, 30000)
 
@@ -56,7 +56,7 @@ function create (options, callback) {
       throw new Error('Received exception error from webtorrent process.' + data.exception)
     })
 
-    var webtorrent_process = spawn(pathUtils.join(__dirname, 'webtorrentProcess.js'), host, port, { detached: true })
+    const webtorrent_process = spawn(pathUtils.join(__dirname, 'webtorrentProcess.js'), host, port, { detached: true })
     webtorrent_process.stderr.on('data', function (data) {
       // logger.debug('Webtorrent process stderr: ', data.toString())
     })
@@ -72,9 +72,9 @@ function create (options, callback) {
 }
 
 function seed (path, callback) {
-  var extension = pathUtils.extname(path)
-  var basename = pathUtils.basename(path, extension)
-  var data = {
+  const extension = pathUtils.extname(path)
+  const basename = pathUtils.basename(path, extension)
+  const data = {
     _id: basename,
     args: {
       path: path
@@ -84,12 +84,12 @@ function seed (path, callback) {
   if (!webtorrent.silent) logger.debug('Node wants to seed %s.', data._id)
 
   // Finish signal
-  var event_key = nodeKey + '.seedDone.' + data._id
+  const event_key = nodeKey + '.seedDone.' + data._id
   ipc.server.on(event_key, function listener (received) {
     if (!webtorrent.silent) logger.debug('Process seeded torrent %s.', received.magnetUri)
 
     // This is a fake object, we just use the magnetUri in this project
-    var torrent = {
+    const torrent = {
       magnetURI: received.magnetUri
     }
 
@@ -101,7 +101,7 @@ function seed (path, callback) {
 }
 
 function add (magnetUri, callback) {
-  var data = {
+  const data = {
     _id: magnetUri,
     args: {
       magnetUri: magnetUri
@@ -111,12 +111,12 @@ function add (magnetUri, callback) {
   if (!webtorrent.silent) logger.debug('Node wants to add ' + data._id)
 
   // Finish signal
-  var event_key = nodeKey + '.addDone.' + data._id
+  const event_key = nodeKey + '.addDone.' + data._id
   ipc.server.on(event_key, function (received) {
     if (!webtorrent.silent) logger.debug('Process added torrent.')
 
     // This is a fake object, we just use the magnetUri in this project
-    var torrent = {
+    const torrent = {
       files: received.files
     }
 
@@ -128,7 +128,7 @@ function add (magnetUri, callback) {
 }
 
 function remove (magnetUri, callback) {
-  var data = {
+  const data = {
     _id: magnetUri,
     args: {
       magnetUri: magnetUri
@@ -138,11 +138,11 @@ function remove (magnetUri, callback) {
   if (!webtorrent.silent) logger.debug('Node wants to stop seeding %s.', data._id)
 
   // Finish signal
-  var event_key = nodeKey + '.removeDone.' + data._id
+  const event_key = nodeKey + '.removeDone.' + data._id
   ipc.server.on(event_key, function (received) {
     if (!webtorrent.silent) logger.debug('Process removed torrent %s.', data._id)
 
-    var err = null
+    let err = null
     if (received.err) err = received.err
 
     ipc.server.off(event_key)
diff --git a/server/lib/webtorrentProcess.js b/server/lib/webtorrentProcess.js
index 7da52523a..c68e97ee4 100644
--- a/server/lib/webtorrentProcess.js
+++ b/server/lib/webtorrentProcess.js
@@ -1,32 +1,32 @@
 'use strict'
 
-var WebTorrent = require('webtorrent')
-var ipc = require('node-ipc')
+const WebTorrent = require('webtorrent')
+const ipc = require('node-ipc')
 
 function webtorrent (args) {
   if (args.length !== 3) {
     throw new Error('Wrong arguments number: ' + args.length + '/3')
   }
 
-  var host = args[1]
-  var port = args[2]
-  var nodeKey = 'webtorrentnode' + port
-  var processKey = 'webtorrentprocess' + port
+  const host = args[1]
+  const port = args[2]
+  const nodeKey = 'webtorrentnode' + port
+  const processKey = 'webtorrentprocess' + port
 
   ipc.config.silent = true
   ipc.config.id = processKey
 
   if (host === 'client' && port === '1') global.WEBTORRENT_ANNOUNCE = []
   else global.WEBTORRENT_ANNOUNCE = 'ws://' + host + ':' + port + '/tracker/socket'
-  var wt = new WebTorrent({ dht: false })
+  const wt = new WebTorrent({ dht: false })
 
   function seed (data) {
-    var args = data.args
-    var path = args.path
-    var _id = data._id
+    const args = data.args
+    const path = args.path
+    const _id = data._id
 
     wt.seed(path, { announceList: '' }, function (torrent) {
-      var to_send = {
+      const to_send = {
         magnetUri: torrent.magnetURI
       }
 
@@ -35,12 +35,12 @@ function webtorrent (args) {
   }
 
   function add (data) {
-    var args = data.args
-    var magnetUri = args.magnetUri
-    var _id = data._id
+    const args = data.args
+    const magnetUri = args.magnetUri
+    const _id = data._id
 
     wt.add(magnetUri, function (torrent) {
-      var to_send = {
+      const to_send = {
         files: []
       }
 
@@ -53,9 +53,9 @@ function webtorrent (args) {
   }
 
   function remove (data) {
-    var args = data.args
-    var magnetUri = args.magnetUri
-    var _id = data._id
+    const args = data.args
+    const magnetUri = args.magnetUri
+    const _id = data._id
 
     try {
       wt.remove(magnetUri, callback)
@@ -65,7 +65,7 @@ function webtorrent (args) {
     }
 
     function callback () {
-      var to_send = {}
+      const to_send = {}
       ipc.of[nodeKey].emit(nodeKey + '.removeDone.' + _id, to_send)
     }
   }
diff --git a/server/middlewares/cache.js b/server/middlewares/cache.js
index 0d3da0075..1b621f6dc 100644
--- a/server/middlewares/cache.js
+++ b/server/middlewares/cache.js
@@ -1,6 +1,6 @@
 'use strict'
 
-var cacheMiddleware = {
+const cacheMiddleware = {
   cache: cache
 }
 
diff --git a/server/middlewares/index.js b/server/middlewares/index.js
index c85899b0c..d85f6261c 100644
--- a/server/middlewares/index.js
+++ b/server/middlewares/index.js
@@ -1,10 +1,10 @@
 'use strict'
 
-var cacheMiddleware = require('./cache')
-var reqValidatorsMiddleware = require('./reqValidators')
-var secureMiddleware = require('./secure')
+const cacheMiddleware = require('./cache')
+const reqValidatorsMiddleware = require('./reqValidators')
+const secureMiddleware = require('./secure')
 
-var middlewares = {
+const middlewares = {
   cache: cacheMiddleware,
   reqValidators: reqValidatorsMiddleware,
   secure: secureMiddleware
diff --git a/server/middlewares/reqValidators/index.js b/server/middlewares/reqValidators/index.js
index 345dbd0e2..c6c5e1309 100644
--- a/server/middlewares/reqValidators/index.js
+++ b/server/middlewares/reqValidators/index.js
@@ -1,10 +1,10 @@
 'use strict'
 
-var podsReqValidators = require('./pods')
-var remoteReqValidators = require('./remote')
-var videosReqValidators = require('./videos')
+const podsReqValidators = require('./pods')
+const remoteReqValidators = require('./remote')
+const videosReqValidators = require('./videos')
 
-var reqValidators = {
+const reqValidators = {
   pods: podsReqValidators,
   remote: remoteReqValidators,
   videos: videosReqValidators
diff --git a/server/middlewares/reqValidators/pods.js b/server/middlewares/reqValidators/pods.js
index ef09d51cf..45e34c1ab 100644
--- a/server/middlewares/reqValidators/pods.js
+++ b/server/middlewares/reqValidators/pods.js
@@ -1,10 +1,10 @@
 'use strict'
 
-var checkErrors = require('./utils').checkErrors
-var friends = require('../../lib/friends')
-var logger = require('../../helpers/logger')
+const checkErrors = require('./utils').checkErrors
+const friends = require('../../lib/friends')
+const logger = require('../../helpers/logger')
 
-var reqValidatorsPod = {
+const reqValidatorsPod = {
   makeFriends: makeFriends,
   podsAdd: podsAdd
 }
diff --git a/server/middlewares/reqValidators/remote.js b/server/middlewares/reqValidators/remote.js
index 88de16b49..3bc0e0f40 100644
--- a/server/middlewares/reqValidators/remote.js
+++ b/server/middlewares/reqValidators/remote.js
@@ -1,9 +1,9 @@
 'use strict'
 
-var checkErrors = require('./utils').checkErrors
-var logger = require('../../helpers/logger')
+const checkErrors = require('./utils').checkErrors
+const logger = require('../../helpers/logger')
 
-var reqValidatorsRemote = {
+const reqValidatorsRemote = {
   remoteVideosAdd: remoteVideosAdd,
   remoteVideosRemove: remoteVideosRemove,
   secureRequest: secureRequest
diff --git a/server/middlewares/reqValidators/utils.js b/server/middlewares/reqValidators/utils.js
index 46c982571..05675c445 100644
--- a/server/middlewares/reqValidators/utils.js
+++ b/server/middlewares/reqValidators/utils.js
@@ -1,16 +1,16 @@
 'use strict'
 
-var util = require('util')
+const util = require('util')
 
-var logger = require('../../helpers/logger')
+const logger = require('../../helpers/logger')
 
-var reqValidatorsUtils = {
+const reqValidatorsUtils = {
   checkErrors: checkErrors
 }
 
 function checkErrors (req, res, next, status_code) {
   if (status_code === undefined) status_code = 400
-  var errors = req.validationErrors()
+  const errors = req.validationErrors()
 
   if (errors) {
     logger.warn('Incorrect request parameters', { path: req.originalUrl, err: errors })
diff --git a/server/middlewares/reqValidators/videos.js b/server/middlewares/reqValidators/videos.js
index b0a6d0360..4057e72cd 100644
--- a/server/middlewares/reqValidators/videos.js
+++ b/server/middlewares/reqValidators/videos.js
@@ -1,11 +1,11 @@
 'use strict'
 
-var checkErrors = require('./utils').checkErrors
-var logger = require('../../helpers/logger')
-var videos = require('../../lib/videos')
-var Videos = require('../../models/videos')
+const checkErrors = require('./utils').checkErrors
+const logger = require('../../helpers/logger')
+const videos = require('../../lib/videos')
+const Videos = require('../../models/videos')
 
-var reqValidatorsVideos = {
+const reqValidatorsVideos = {
   videosAdd: videosAdd,
   videosGet: videosGet,
   videosRemove: videosRemove,
diff --git a/server/middlewares/secure.js b/server/middlewares/secure.js
index bfd28316a..9ecbf5df1 100644
--- a/server/middlewares/secure.js
+++ b/server/middlewares/secure.js
@@ -1,15 +1,15 @@
 'use strict'
 
-var logger = require('../helpers/logger')
-var peertubeCrypto = require('../helpers/peertubeCrypto')
-var Pods = require('../models/pods')
+const logger = require('../helpers/logger')
+const peertubeCrypto = require('../helpers/peertubeCrypto')
+const Pods = require('../models/pods')
 
-var secureMiddleware = {
+const secureMiddleware = {
   decryptBody: decryptBody
 }
 
 function decryptBody (req, res, next) {
-  var url = req.body.signature.url
+  const url = req.body.signature.url
   Pods.findByUrl(url, function (err, pod) {
     if (err) {
       logger.error('Cannot get signed url in decryptBody.', { error: err })
@@ -23,7 +23,7 @@ function decryptBody (req, res, next) {
 
     logger.debug('Decrypting body from %s.', url)
 
-    var signature_ok = peertubeCrypto.checkSignature(pod.publicKey, url, req.body.signature.signature)
+    const signature_ok = peertubeCrypto.checkSignature(pod.publicKey, url, req.body.signature.signature)
 
     if (signature_ok === true) {
       peertubeCrypto.decrypt(req.body.key, req.body.data, function (err, decrypted) {
diff --git a/server/models/pods.js b/server/models/pods.js
index 57ed20292..4e21001f5 100644
--- a/server/models/pods.js
+++ b/server/models/pods.js
@@ -1,22 +1,22 @@
 'use strict'
 
-var mongoose = require('mongoose')
+const mongoose = require('mongoose')
 
-var constants = require('../initializers/constants')
-var logger = require('../helpers/logger')
+const constants = require('../initializers/constants')
+const logger = require('../helpers/logger')
 
 // ---------------------------------------------------------------------------
 
-var podsSchema = mongoose.Schema({
+const podsSchema = mongoose.Schema({
   url: String,
   publicKey: String,
   score: { type: Number, max: constants.FRIEND_BASE_SCORE }
 })
-var PodsDB = mongoose.model('pods', podsSchema)
+const PodsDB = mongoose.model('pods', podsSchema)
 
 // ---------------------------------------------------------------------------
 
-var Pods = {
+const Pods = {
   add: add,
   count: count,
   findByUrl: findByUrl,
@@ -31,7 +31,7 @@ var Pods = {
 // TODO: check if the pod is not already a friend
 function add (data, callback) {
   if (!callback) callback = function () {}
-  var params = {
+  const params = {
     url: data.url,
     publicKey: data.publicKey,
     score: constants.FRIEND_BASE_SCORE
diff --git a/server/models/poolRequests.js b/server/models/poolRequests.js
index 970315597..28093a94c 100644
--- a/server/models/poolRequests.js
+++ b/server/models/poolRequests.js
@@ -1,21 +1,21 @@
 'use strict'
 
-var mongoose = require('mongoose')
+const mongoose = require('mongoose')
 
-var logger = require('../helpers/logger')
+const logger = require('../helpers/logger')
 
 // ---------------------------------------------------------------------------
 
-var poolRequestsSchema = mongoose.Schema({
+const poolRequestsSchema = mongoose.Schema({
   type: String,
   id: String, // Special id to find duplicates (video created we want to remove...)
   request: mongoose.Schema.Types.Mixed
 })
-var PoolRequestsDB = mongoose.model('poolRequests', poolRequestsSchema)
+const PoolRequestsDB = mongoose.model('poolRequests', poolRequestsSchema)
 
 // ---------------------------------------------------------------------------
 
-var PoolRequests = {
+const PoolRequests = {
   create: create,
   findById: findById,
   list: list,
diff --git a/server/models/videos.js b/server/models/videos.js
index fd02ec9e1..0141cbb7f 100644
--- a/server/models/videos.js
+++ b/server/models/videos.js
@@ -1,33 +1,33 @@
 'use strict'
 
-var async = require('async')
-var config = require('config')
-var dz = require('dezalgo')
-var fs = require('fs')
-var mongoose = require('mongoose')
-var path = require('path')
+const async = require('async')
+const config = require('config')
+const dz = require('dezalgo')
+const fs = require('fs')
+const mongoose = require('mongoose')
+const path = require('path')
 
-var logger = require('../helpers/logger')
+const logger = require('../helpers/logger')
 
-var http = config.get('webserver.https') === true ? 'https' : 'http'
-var host = config.get('webserver.host')
-var port = config.get('webserver.port')
-var uploadDir = path.join(__dirname, '..', '..', config.get('storage.uploads'))
+const http = config.get('webserver.https') === true ? 'https' : 'http'
+const host = config.get('webserver.host')
+const port = config.get('webserver.port')
+const uploadDir = path.join(__dirname, '..', '..', config.get('storage.uploads'))
 
 // ---------------------------------------------------------------------------
 
-var videosSchema = mongoose.Schema({
+const videosSchema = mongoose.Schema({
   name: String,
   namePath: String,
   description: String,
   magnetUri: String,
   podUrl: String
 })
-var VideosDB = mongoose.model('videos', videosSchema)
+const VideosDB = mongoose.model('videos', videosSchema)
 
 // ---------------------------------------------------------------------------
 
-var Videos = {
+const Videos = {
   add: add,
   addRemotes: addRemotes,
   get: get,
@@ -43,7 +43,7 @@ var Videos = {
 function add (video, callback) {
   logger.info('Adding %s video to database.', video.name)
 
-  var params = video
+  const params = video
   params.podUrl = http + '://' + host + ':' + port
 
   VideosDB.create(params, function (err, video) {
@@ -60,13 +60,13 @@ function add (video, callback) {
 function addRemotes (videos, callback) {
   if (!callback) callback = function () {}
 
-  var to_add = []
+  const to_add = []
 
   async.each(videos, function (video, callback_each) {
     callback_each = dz(callback_each)
     logger.debug('Add remote video from pod: %s', video.podUrl)
 
-    var params = {
+    const params = {
       name: video.name,
       namePath: null,
       description: video.description,
@@ -159,7 +159,7 @@ function removeRemotesOfByMagnetUris (fromUrl, magnetUris, callback) {
       return callback(err)
     }
 
-    var to_remove = []
+    const to_remove = []
     async.each(videos, function (video, callback_async) {
       callback_async = dz(callback_async)
 
diff --git a/server/tests/api/checkParams.js b/server/tests/api/checkParams.js
index 01b620873..b31b0e894 100644
--- a/server/tests/api/checkParams.js
+++ b/server/tests/api/checkParams.js
@@ -1,27 +1,27 @@
 'use strict'
 
-var async = require('async')
-var chai = require('chai')
-var expect = chai.expect
-var pathUtils = require('path')
-var request = require('supertest')
+const async = require('async')
+const chai = require('chai')
+const expect = chai.expect
+const pathUtils = require('path')
+const request = require('supertest')
 
-var utils = require('./utils')
+const utils = require('./utils')
 
 describe('Test parameters validator', function () {
-  var app = null
-  var url = ''
+  let app = null
+  let url = ''
 
   function makePostRequest (path, fields, attach, done, fail) {
-    var status_code = 400
+    let status_code = 400
     if (fail !== undefined && fail === false) status_code = 200
 
-    var req = request(url)
+    const req = request(url)
       .post(path)
       .set('Accept', 'application/json')
 
     Object.keys(fields).forEach(function (field) {
-      var value = fields[field]
+      const value = fields[field]
       req.field(field, value)
     })
 
@@ -29,7 +29,7 @@ describe('Test parameters validator', function () {
   }
 
   function makePostBodyRequest (path, fields, done, fail) {
-    var status_code = 400
+    let status_code = 400
     if (fail !== undefined && fail === false) status_code = 200
 
     request(url)
@@ -59,16 +59,16 @@ describe('Test parameters validator', function () {
   })
 
   describe('Of the pods API', function () {
-    var path = '/api/v1/pods/'
+    const path = '/api/v1/pods/'
 
     describe('When adding a pod', function () {
       it('Should fail with nothing', function (done) {
-        var data = {}
+        const data = {}
         makePostBodyRequest(path, data, done)
       })
 
       it('Should fail without public key', function (done) {
-        var data = {
+        const data = {
           data: {
             url: 'http://coucou.com'
           }
@@ -77,7 +77,7 @@ describe('Test parameters validator', function () {
       })
 
       it('Should fail without an url', function (done) {
-        var data = {
+        const data = {
           data: {
             publicKey: 'mysuperpublickey'
           }
@@ -86,7 +86,7 @@ describe('Test parameters validator', function () {
       })
 
       it('Should fail with an incorrect url', function (done) {
-        var data = {
+        const data = {
           data: {
             url: 'coucou.com',
             publicKey: 'mysuperpublickey'
@@ -102,7 +102,7 @@ describe('Test parameters validator', function () {
       })
 
       it('Should succeed with the correct parameters', function (done) {
-        var data = {
+        const data = {
           data: {
             url: 'http://coucou.com',
             publicKey: 'mysuperpublickey'
@@ -114,7 +114,7 @@ describe('Test parameters validator', function () {
   })
 
   describe('Of the videos API', function () {
-    var path = '/api/v1/videos/'
+    const path = '/api/v1/videos/'
 
     describe('When searching a video', function () {
       it('Should fail with nothing', function (done) {
@@ -127,81 +127,81 @@ describe('Test parameters validator', function () {
 
     describe('When adding a video', function () {
       it('Should fail with nothing', function (done) {
-        var data = {}
-        var attach = {}
+        const data = {}
+        const attach = {}
         makePostRequest(path, data, attach, done)
       })
 
       it('Should fail without name', function (done) {
-        var data = {
+        const data = {
           description: 'my super description'
         }
-        var attach = {
+        const attach = {
           'input_video': pathUtils.join(__dirname, 'fixtures', 'video_short.webm')
         }
         makePostRequest(path, data, attach, done)
       })
 
       it('Should fail with a long name', function (done) {
-        var data = {
+        const data = {
           name: 'My very very very very very very very very very very very very very very very very long name',
           description: 'my super description'
         }
-        var attach = {
+        const attach = {
           'input_video': pathUtils.join(__dirname, 'fixtures', 'video_short.webm')
         }
         makePostRequest(path, data, attach, done)
       })
 
       it('Should fail without description', function (done) {
-        var data = {
+        const data = {
           name: 'my super name'
         }
-        var attach = {
+        const attach = {
           'input_video': pathUtils.join(__dirname, 'fixtures', 'video_short.webm')
         }
         makePostRequest(path, data, attach, done)
       })
 
       it('Should fail with a long description', function (done) {
-        var data = {
+        const data = {
           name: 'my super name',
           description: 'my super description which is very very very very very very very very very very very very very very' +
                        'very very very very very very very very very very very very very very very very very very very very very' +
                        'very very very very very very very very very very very very very very very long'
         }
-        var attach = {
+        const attach = {
           'input_video': pathUtils.join(__dirname, 'fixtures', 'video_short.webm')
         }
         makePostRequest(path, data, attach, done)
       })
 
       it('Should fail without an input file', function (done) {
-        var data = {
+        const data = {
           name: 'my super name',
           description: 'my super description'
         }
-        var attach = {}
+        const attach = {}
         makePostRequest(path, data, attach, done)
       })
 
       it('Should fail without an incorrect input file', function (done) {
-        var data = {
+        const data = {
           name: 'my super name',
           description: 'my super description'
         }
-        var attach = {
+        const attach = {
           'input_video': pathUtils.join(__dirname, '..', 'fixtures', 'video_short_fake.webm')
         }
         makePostRequest(path, data, attach, done)
       })
 
       it('Should succeed with the correct parameters', function (done) {
-        var data = {
+        const data = {
           name: 'my super name',
           description: 'my super description'
         }
-        var attach = {
+        const attach = {
           'input_video': pathUtils.join(__dirname, 'fixtures', 'video_short.webm')
         }
         makePostRequest(path, data, attach, function () {
diff --git a/server/tests/api/friendsAdvanced.js b/server/tests/api/friendsAdvanced.js
index 9838d890f..6c4b7567f 100644
--- a/server/tests/api/friendsAdvanced.js
+++ b/server/tests/api/friendsAdvanced.js
@@ -1,14 +1,14 @@
 'use strict'
 
-var async = require('async')
-var chai = require('chai')
-var expect = chai.expect
+const async = require('async')
+const chai = require('chai')
+const expect = chai.expect
 
-var utils = require('./utils')
+const utils = require('./utils')
 
 describe('Test advanced friends', function () {
-  var apps = []
-  var urls = []
+  let apps = []
+  let urls = []
 
   function makeFriends (pod_number, callback) {
     return utils.makeFriends(urls[pod_number - 1], callback)
@@ -23,9 +23,9 @@ describe('Test advanced friends', function () {
   }
 
   function uploadVideo (pod_number, callback) {
-    var name = 'my super video'
-    var description = 'my super description'
-    var fixture = 'video_short.webm'
+    const name = 'my super video'
+    const description = 'my super description'
+    const fixture = 'video_short.webm'
 
     return utils.uploadVideo(urls[pod_number - 1], name, description, fixture, callback)
   }
@@ -171,9 +171,9 @@ describe('Test advanced friends', function () {
           if (err) throw err
 
           // Pod 4 should not be our friend
-          var result = res.body
+          const result = res.body
           expect(result.length).to.equal(3)
-          for (var pod of result) {
+          for (const pod of result) {
             expect(pod.url).not.equal(urls[3])
           }
 
diff --git a/server/tests/api/friendsBasic.js b/server/tests/api/friendsBasic.js
index 328724936..62eac51ec 100644
--- a/server/tests/api/friendsBasic.js
+++ b/server/tests/api/friendsBasic.js
@@ -1,19 +1,19 @@
 'use strict'
 
-var async = require('async')
-var chai = require('chai')
-var expect = chai.expect
-var request = require('supertest')
+const async = require('async')
+const chai = require('chai')
+const expect = chai.expect
+const request = require('supertest')
 
-var utils = require('./utils')
+const utils = require('./utils')
 
 describe('Test basic friends', function () {
-  var apps = []
-  var urls = []
+  let apps = []
+  let urls = []
 
   function testMadeFriends (urls, url_to_test, callback) {
-    var friends = []
-    for (var i = 0; i < urls.length; i++) {
+    const friends = []
+    for (let i = 0; i < urls.length; i++) {
       if (urls[i] === url_to_test) continue
       friends.push(urls[i])
     }
@@ -21,13 +21,13 @@ describe('Test basic friends', function () {
     utils.getFriendsList(url_to_test, function (err, res) {
       if (err) throw err
 
-      var result = res.body
-      var result_urls = [ result[0].url, result[1].url ]
+      const result = res.body
+      const result_urls = [ result[0].url, result[1].url ]
       expect(result).to.be.an('array')
       expect(result.length).to.equal(2)
       expect(result_urls[0]).to.not.equal(result_urls[1])
 
-      var error_string = 'Friends url do not correspond for ' + url_to_test
+      const error_string = 'Friends url do not correspond for ' + url_to_test
       expect(friends).to.contain(result_urls[0], error_string)
       expect(friends).to.contain(result_urls[1], error_string)
       callback()
@@ -50,7 +50,7 @@ describe('Test basic friends', function () {
       utils.getFriendsList(url, function (err, res) {
         if (err) throw err
 
-        var result = res.body
+        const result = res.body
         expect(result).to.be.an('array')
         expect(result.length).to.equal(0)
         callback()
@@ -61,7 +61,7 @@ describe('Test basic friends', function () {
   it('Should make friends', function (done) {
     this.timeout(10000)
 
-    var path = '/api/v1/pods/makefriends'
+    const path = '/api/v1/pods/makefriends'
 
     async.series([
       // The second pod make friend with the third
@@ -81,7 +81,7 @@ describe('Test basic friends', function () {
         utils.getFriendsList(urls[1], function (err, res) {
           if (err) throw err
 
-          var result = res.body
+          const result = res.body
           expect(result).to.be.an('array')
           expect(result.length).to.equal(1)
           expect(result[0].url).to.be.equal(urls[2])
@@ -94,7 +94,7 @@ describe('Test basic friends', function () {
         utils.getFriendsList(urls[2], function (err, res) {
           if (err) throw err
 
-          var result = res.body
+          const result = res.body
           expect(result).to.be.an('array')
           expect(result.length).to.equal(1)
           expect(result[0].url).to.be.equal(urls[1])
@@ -139,7 +139,7 @@ describe('Test basic friends', function () {
         utils.getFriendsList(urls[1], function (err, res) {
           if (err) throw err
 
-          var result = res.body
+          const result = res.body
           expect(result).to.be.an('array')
           expect(result.length).to.equal(0)
 
@@ -152,7 +152,7 @@ describe('Test basic friends', function () {
           utils.getFriendsList(url, function (err, res) {
             if (err) throw err
 
-            var result = res.body
+            const result = res.body
             expect(result).to.be.an('array')
             expect(result.length).to.equal(1)
             expect(result[0].url).not.to.be.equal(urls[1])
diff --git a/server/tests/api/multiplePods.js b/server/tests/api/multiplePods.js
index 9fdd0f308..e8b182622 100644
--- a/server/tests/api/multiplePods.js
+++ b/server/tests/api/multiplePods.js
@@ -1,18 +1,18 @@
 'use strict'
 
-var async = require('async')
-var chai = require('chai')
-var expect = chai.expect
-var pathUtils = require('path')
+const async = require('async')
+const chai = require('chai')
+const expect = chai.expect
+const pathUtils = require('path')
 
-var utils = require('./utils')
-var webtorrent = require(pathUtils.join(__dirname, '../../lib/webtorrent'))
+const utils = require('./utils')
+const webtorrent = require(pathUtils.join(__dirname, '../../lib/webtorrent'))
 webtorrent.silent = true
 
 describe('Test multiple pods', function () {
-  var apps = []
-  var urls = []
-  var to_remove = []
+  let apps = []
+  let urls = []
+  const to_remove = []
 
   before(function (done) {
     this.timeout(30000)
@@ -73,15 +73,15 @@ describe('Test multiple pods', function () {
           if (err) throw err
 
           async.each(urls, function (url, callback) {
-            var base_magnet = null
+            let base_magnet = null
 
             utils.getVideosList(url, function (err, res) {
               if (err) throw err
 
-              var videos = res.body
+              const videos = res.body
               expect(videos).to.be.an('array')
               expect(videos.length).to.equal(1)
-              var video = videos[0]
+              const video = videos[0]
               expect(video.name).to.equal('my super name for pod 1')
               expect(video.description).to.equal('my super description for pod 1')
               expect(video.podUrl).to.equal('http://localhost:9001')
@@ -116,15 +116,15 @@ describe('Test multiple pods', function () {
           if (err) throw err
 
           async.each(urls, function (url, callback) {
-            var base_magnet = null
+            let base_magnet = null
 
             utils.getVideosList(url, function (err, res) {
               if (err) throw err
 
-              var videos = res.body
+              const videos = res.body
               expect(videos).to.be.an('array')
               expect(videos.length).to.equal(2)
-              var video = videos[1]
+              const video = videos[1]
               expect(video.name).to.equal('my super name for pod 2')
               expect(video.description).to.equal('my super description for pod 2')
               expect(video.podUrl).to.equal('http://localhost:9002')
@@ -160,16 +160,16 @@ describe('Test multiple pods', function () {
         function (err) {
           if (err) throw err
 
-          var base_magnet = null
+          let base_magnet = null
           // All pods should have this video
           async.each(urls, function (url, callback) {
             utils.getVideosList(url, function (err, res) {
               if (err) throw err
 
-              var videos = res.body
+              const videos = res.body
               expect(videos).to.be.an('array')
               expect(videos.length).to.equal(4)
-              var video = videos[2]
+              let video = videos[2]
               expect(video.name).to.equal('my super name for pod 3')
               expect(video.description).to.equal('my super description for pod 3')
               expect(video.podUrl).to.equal('http://localhost:9003')
@@ -204,7 +204,7 @@ describe('Test multiple pods', function () {
       utils.getVideosList(urls[2], function (err, res) {
         if (err) throw err
 
-        var video = res.body[0]
+        const video = res.body[0]
         to_remove.push(res.body[2]._id)
         to_remove.push(res.body[3]._id)
 
@@ -225,7 +225,7 @@ describe('Test multiple pods', function () {
       utils.getVideosList(urls[0], function (err, res) {
         if (err) throw err
 
-        var video = res.body[1]
+        const video = res.body[1]
 
         webtorrent.add(video.magnetUri, function (torrent) {
           expect(torrent.files).to.exist
@@ -244,7 +244,7 @@ describe('Test multiple pods', function () {
       utils.getVideosList(urls[1], function (err, res) {
         if (err) throw err
 
-        var video = res.body[2]
+        const video = res.body[2]
 
         webtorrent.add(video.magnetUri, function (torrent) {
           expect(torrent.files).to.exist
@@ -263,7 +263,7 @@ describe('Test multiple pods', function () {
       utils.getVideosList(urls[0], function (err, res) {
         if (err) throw err
 
-        var video = res.body[3]
+        const video = res.body[3]
 
         webtorrent.add(video.magnetUri, function (torrent) {
           expect(torrent.files).to.exist
@@ -297,7 +297,7 @@ describe('Test multiple pods', function () {
         utils.getVideosList(url, function (err, res) {
           if (err) throw err
 
-          var videos = res.body
+          const videos = res.body
           expect(videos).to.be.an('array')
           expect(videos.length).to.equal(2)
           expect(videos[0]._id).not.to.equal(videos[1]._id)
diff --git a/server/tests/api/singlePod.js b/server/tests/api/singlePod.js
index d572aacf6..14f893f13 100644
--- a/server/tests/api/singlePod.js
+++ b/server/tests/api/singlePod.js
@@ -1,20 +1,20 @@
 'use strict'
 
-var async = require('async')
-var chai = require('chai')
-var expect = chai.expect
-var fs = require('fs')
-var pathUtils = require('path')
+const async = require('async')
+const chai = require('chai')
+const expect = chai.expect
+const fs = require('fs')
+const pathUtils = require('path')
 
-var webtorrent = require(pathUtils.join(__dirname, '../../lib/webtorrent'))
+const webtorrent = require(pathUtils.join(__dirname, '../../lib/webtorrent'))
 webtorrent.silent = true
 
-var utils = require('./utils')
+const utils = require('./utils')
 
 describe('Test a single pod', function () {
-  var app = null
-  var url = ''
-  var video_id = -1
+  let app = null
+  let url = ''
+  let video_id = -1
 
   before(function (done) {
     this.timeout(20000)
@@ -62,7 +62,7 @@ describe('Test a single pod', function () {
       expect(res.body).to.be.an('array')
       expect(res.body.length).to.equal(1)
 
-      var video = res.body[0]
+      const video = res.body[0]
       expect(video.name).to.equal('my super name')
       expect(video.description).to.equal('my super description')
       expect(video.podUrl).to.equal('http://localhost:9001')
@@ -87,7 +87,7 @@ describe('Test a single pod', function () {
       expect(res.body).to.be.an('array')
       expect(res.body.length).to.equal(1)
 
-      var video = res.body[0]
+      const video = res.body[0]
       expect(video.name).to.equal('my super name')
       expect(video.description).to.equal('my super description')
       expect(video.podUrl).to.equal('http://localhost:9001')
diff --git a/server/tests/api/utils.js b/server/tests/api/utils.js
index 60c3c8d4e..05142085f 100644
--- a/server/tests/api/utils.js
+++ b/server/tests/api/utils.js
@@ -1,12 +1,12 @@
 'use strict'
 
-var child_process = require('child_process')
-var exec = child_process.exec
-var fork = child_process.fork
-var pathUtils = require('path')
-var request = require('supertest')
+const child_process = require('child_process')
+const exec = child_process.exec
+const fork = child_process.fork
+const pathUtils = require('path')
+const request = require('supertest')
 
-var testUtils = {
+const testUtils = {
   flushTests: flushTests,
   getFriendsList: getFriendsList,
   getVideosList: getVideosList,
@@ -26,7 +26,7 @@ function flushTests (callback) {
 }
 
 function getFriendsList (url, end) {
-  var path = '/api/v1/pods/'
+  const path = '/api/v1/pods/'
 
   request(url)
     .get(path)
@@ -37,7 +37,7 @@ function getFriendsList (url, end) {
 }
 
 function getVideosList (url, end) {
-  var path = '/api/v1/videos'
+  const path = '/api/v1/videos'
 
   request(url)
     .get(path)
@@ -53,7 +53,7 @@ function makeFriends (url, expected_status, callback) {
     expected_status = 204
   }
 
-  var path = '/api/v1/pods/makefriends'
+  const path = '/api/v1/pods/makefriends'
 
   // The first pod make friend with the third
   request(url)
@@ -69,7 +69,7 @@ function makeFriends (url, expected_status, callback) {
 }
 
 function quitFriends (url, callback) {
-  var path = '/api/v1/pods/quitfriends'
+  const path = '/api/v1/pods/quitfriends'
 
   // The first pod make friend with the third
   request(url)
@@ -85,7 +85,7 @@ function quitFriends (url, callback) {
 }
 
 function removeVideo (url, id, end) {
-  var path = '/api/v1/videos'
+  const path = '/api/v1/videos'
 
   request(url)
     .delete(path + '/' + id)
@@ -95,9 +95,9 @@ function removeVideo (url, id, end) {
 }
 
 function flushAndRunMultipleServers (total_servers, serversRun) {
-  var apps = []
-  var urls = []
-  var i = 0
+  let apps = []
+  let urls = []
+  let i = 0
 
   function anotherServerDone (number, app, url) {
     apps[number - 1] = app
@@ -109,41 +109,39 @@ function flushAndRunMultipleServers (total_servers, serversRun) {
   }
 
   flushTests(function () {
-    for (var j = 1; j <= total_servers; j++) {
-      (function (k) { // TODO: ES6 with let
-        // For the virtual buffer
-        setTimeout(function () {
-          runServer(k, function (app, url) {
-            anotherServerDone(k, app, url)
-          })
-        }, 1000 * k)
-      })(j)
+    for (let j = 1; j <= total_servers; j++) {
+      // For the virtual buffer
+      setTimeout(function () {
+        runServer(j, function (app, url) {
+          anotherServerDone(j, app, url)
+        })
+      }, 1000 * j)
     }
   })
 }
 
 function runServer (number, callback) {
-  var port = 9000 + number
-  var server_run_string = {
+  const port = 9000 + number
+  const server_run_string = {
     'Connected to mongodb': false,
     'Server listening on port': false
   }
 
   // Share the environment
-  var env = Object.create(process.env)
+  const env = Object.create(process.env)
   env.NODE_ENV = 'test'
   env.NODE_APP_INSTANCE = number
-  var options = {
+  const options = {
     silent: true,
     env: env,
     detached: true
   }
 
-  var app = fork(pathUtils.join(__dirname, '../../../server.js'), [], options)
+  const app = fork(pathUtils.join(__dirname, '../../../server.js'), [], options)
   app.stdout.on('data', function onStdout (data) {
-    var dont_continue = false
+    let dont_continue = false
     // Check if all required sentences are here
-    for (var key of Object.keys(server_run_string)) {
+    for (const key of Object.keys(server_run_string)) {
       if (data.toString().indexOf(key) !== -1) server_run_string[key] = true
       if (server_run_string[key] === false) dont_continue = true
     }
@@ -157,7 +155,7 @@ function runServer (number, callback) {
 }
 
 function searchVideo (url, search, end) {
-  var path = '/api/v1/videos'
+  const path = '/api/v1/videos'
 
   request(url)
     .get(path + '/search/' + search)
@@ -168,7 +166,7 @@ function searchVideo (url, search, end) {
 }
 
 function uploadVideo (url, name, description, fixture, end) {
-  var path = '/api/v1/videos'
+  const path = '/api/v1/videos'
 
   request(url)
     .post(path)
diff --git a/server/tests/index.js b/server/tests/index.js
index ccebbfe51..cb177b87c 100644
--- a/server/tests/index.js
+++ b/server/tests/index.js
@@ -1,6 +1,4 @@
-;(function () {
-  'use strict'
+'use strict'
 
-  // Order of the tests we want to execute
-  require('./api/')
-})()
+// Order of the tests we want to execute
+require('./api/')