diff --git a/src/ui/UiApp.js b/src/ui/UiApp.js
index 4e6fcaa36ef80..8967b528228d6 100644
--- a/src/ui/UiApp.js
+++ b/src/ui/UiApp.js
@@ -1,6 +1,6 @@
-var _ = require('lodash');
+const _ = require('lodash');
 var { join } = require('path');
-var autoload = require('./autoload');
+const autoload = require('./autoload');
 
 class UiApp {
   constructor(uiExports, spec) {
diff --git a/src/ui/UiAppCollection.js b/src/ui/UiAppCollection.js
index e4eda77fb0ede..79456e57773d2 100644
--- a/src/ui/UiAppCollection.js
+++ b/src/ui/UiAppCollection.js
@@ -1,8 +1,8 @@
-let _ = require('lodash');
-let UiApp = require('./UiApp');
-let Collection = require('requirefrom')('src')('utils/Collection');
+const _ = require('lodash');
+const UiApp = require('./UiApp');
+const Collection = require('requirefrom')('src')('utils/Collection');
 
-let byIdCache = Symbol('byId');
+const byIdCache = Symbol('byId');
 
 module.exports = class UiAppCollection extends Collection {
 
@@ -25,7 +25,7 @@ module.exports = class UiAppCollection extends Collection {
       return this.hidden.new(spec);
     }
 
-    let app = new UiApp(this.uiExports, spec);
+    const app = new UiApp(this.uiExports, spec);
 
     if (_.includes(this.claimedIds, app.id)) {
       throw new Error('Unable to create two apps with the id ' + app.id + '.');
diff --git a/src/ui/UiBundle.js b/src/ui/UiBundle.js
index b610c24b7b4d0..0a37e38e03cf1 100644
--- a/src/ui/UiBundle.js
+++ b/src/ui/UiBundle.js
@@ -1,10 +1,10 @@
 
 let { join } = require('path');
 let { promisify } = require('bluebird');
-let read = promisify(require('fs').readFile);
-let write = promisify(require('fs').writeFile);
-let unlink = promisify(require('fs').unlink);
-let stat = promisify(require('fs').stat);
+const read = promisify(require('fs').readFile);
+const write = promisify(require('fs').writeFile);
+const unlink = promisify(require('fs').unlink);
+const stat = promisify(require('fs').stat);
 
 module.exports = class UiBundle {
   constructor(opts) {
@@ -15,7 +15,7 @@ module.exports = class UiBundle {
     this.template = opts.template;
     this.env = opts.env;
 
-    let pathBase = join(this.env.workingDir, this.id);
+    const pathBase = join(this.env.workingDir, this.id);
     this.entryPath = `${pathBase}.entry.js`;
     this.outputPath = `${pathBase}.bundle.js`;
 
@@ -30,7 +30,7 @@ module.exports = class UiBundle {
 
   async readEntryFile() {
     try {
-      let content = await read(this.entryPath);
+      const content = await read(this.entryPath);
       return content.toString('utf8');
     }
     catch (e) {
diff --git a/src/ui/UiBundleCollection.js b/src/ui/UiBundleCollection.js
index 328c03dad1568..e2083f0f7444b 100644
--- a/src/ui/UiBundleCollection.js
+++ b/src/ui/UiBundleCollection.js
@@ -2,14 +2,14 @@ let { pull, transform, pluck } = require('lodash');
 let { join } = require('path');
 let { resolve, promisify } = require('bluebird');
 let { makeRe } = require('minimatch');
-let rimraf = promisify(require('rimraf'));
-let mkdirp = promisify(require('mkdirp'));
-let unlink = promisify(require('fs').unlink);
-let readdir = promisify(require('fs').readdir);
-let readSync = require('fs').readFileSync;
+const rimraf = promisify(require('rimraf'));
+const mkdirp = promisify(require('mkdirp'));
+const unlink = promisify(require('fs').unlink);
+const readdir = promisify(require('fs').readdir);
+const readSync = require('fs').readFileSync;
 
-let UiBundle = require('./UiBundle');
-let appEntryTemplate = require('./appEntryTemplate');
+const UiBundle = require('./UiBundle');
+const appEntryTemplate = require('./appEntryTemplate');
 
 class UiBundleCollection {
   constructor(bundlerEnv, filter) {
@@ -48,9 +48,9 @@ class UiBundleCollection {
       case 1:
         return `bundle for ${this.each[0].id}`;
       default:
-        var ids = this.getIds();
-        var last = ids.pop();
-        var commas = ids.join(', ');
+        const ids = this.getIds();
+        const last = ids.pop();
+        const commas = ids.join(', ');
         return `bundles for ${commas} and ${last}`;
     }
   }
@@ -63,8 +63,8 @@ class UiBundleCollection {
     await this.ensureDir();
 
     for (let bundle of this.each) {
-      let existing = await bundle.readEntryFile();
-      let expected = bundle.renderContent();
+      const existing = await bundle.readEntryFile();
+      const expected = bundle.renderContent();
 
       if (existing !== expected) {
         await bundle.writeEntryFile();
@@ -74,10 +74,10 @@ class UiBundleCollection {
   }
 
   async getInvalidBundles() {
-    let invalids = new UiBundleCollection(this.env);
+    const invalids = new UiBundleCollection(this.env);
 
     for (let bundle of this.each) {
-      let exists = await bundle.checkForExistingOutput();
+      const exists = await bundle.checkForExistingOutput();
       if (!exists) {
         invalids.add(bundle);
       }
diff --git a/src/ui/UiBundlerEnv.js b/src/ui/UiBundlerEnv.js
index 74a2195d152c5..d01e8cdcd4eb4 100644
--- a/src/ui/UiBundlerEnv.js
+++ b/src/ui/UiBundlerEnv.js
@@ -1,12 +1,12 @@
 let { includes, flow, escapeRegExp } = require('lodash');
 let { isString, isArray, isPlainObject, get } = require('lodash');
 let { keys } = require('lodash');
-let fromRoot = require('../utils/fromRoot');
+const fromRoot = require('../utils/fromRoot');
 
-let asRegExp = flow(
+const asRegExp = flow(
   escapeRegExp,
   function (path) {
-    let last = path.slice(-1);
+    const last = path.slice(-1);
     if (last === '/' || last === '\\') {
       // match a directory explicitly
       return path + '.*';
@@ -18,7 +18,7 @@ let asRegExp = flow(
   RegExp
 );
 
-let arr = v => [].concat(v || []);
+const arr = v => [].concat(v || []);
 
 module.exports = class UiBundlerEnv {
   constructor(workingDir) {
@@ -58,7 +58,7 @@ module.exports = class UiBundlerEnv {
   }
 
   consumePlugin(plugin) {
-    let tag = `${plugin.id}@${plugin.version}`;
+    const tag = `${plugin.id}@${plugin.version}`;
     if (includes(this.pluginInfo, tag)) return;
 
     if (plugin.publicDir) {
@@ -141,7 +141,7 @@ module.exports = class UiBundlerEnv {
 
     this.aliases[id] = path;
 
-    let loader = [];
+    const loader = [];
     if (imports) {
       loader.push(`imports?${imports}`);
     }
@@ -153,10 +153,10 @@ module.exports = class UiBundlerEnv {
   }
 
   claim(id, pluginId) {
-    let owner = pluginId ? `Plugin ${pluginId}` : 'Kibana Server';
+    const owner = pluginId ? `Plugin ${pluginId}` : 'Kibana Server';
 
     // TODO(spalger): we could do a lot more to detect colliding module defs
-    var existingOwner = this.aliasOwners[id] || this.aliasOwners[`${id}$`];
+    const existingOwner = this.aliasOwners[id] || this.aliasOwners[`${id}$`];
 
     if (existingOwner) {
       throw new TypeError(`${owner} attempted to override export "${id}" from ${existingOwner}`);
diff --git a/src/ui/UiExports.js b/src/ui/UiExports.js
index 4daf11f87801d..cd0fd4f73b8c2 100644
--- a/src/ui/UiExports.js
+++ b/src/ui/UiExports.js
@@ -1,7 +1,7 @@
-var _ = require('lodash');
-var minimatch = require('minimatch');
+const _ = require('lodash');
+const minimatch = require('minimatch');
 
-var UiAppCollection = require('./UiAppCollection');
+const UiAppCollection = require('./UiAppCollection');
 
 class UiExports {
   constructor({ urlBasePath }) {
@@ -16,10 +16,10 @@ class UiExports {
   consumePlugin(plugin) {
     plugin.apps = new UiAppCollection(this);
 
-    var types = _.keys(plugin.uiExportsSpecs);
+    const types = _.keys(plugin.uiExportsSpecs);
     if (!types) return false;
 
-    var unkown = _.reject(types, this.exportConsumer, this);
+    const unkown = _.reject(types, this.exportConsumer, this);
     if (unkown.length) {
       throw new Error('unknown export types ' + unkown.join(', ') + ' in plugin ' + plugin.id);
     }
@@ -40,7 +40,7 @@ class UiExports {
   exportConsumer(type) {
     for (let consumer of this.consumers) {
       if (!consumer.exportConsumer) continue;
-      let fn = consumer.exportConsumer(type);
+      const fn = consumer.exportConsumer(type);
       if (fn) return fn;
     }
 
@@ -49,7 +49,7 @@ class UiExports {
       case 'apps':
         return (plugin, specs) => {
           for (let spec of [].concat(specs || [])) {
-            let app = this.apps.new(_.defaults({}, spec, {
+            const app = this.apps.new(_.defaults({}, spec, {
               id: plugin.id,
               urlBasePath: this.urlBasePath
             }));
@@ -80,9 +80,9 @@ class UiExports {
   }
 
   find(patterns) {
-    var aliases = this.aliases;
-    var names = _.keys(aliases);
-    var matcher = _.partialRight(minimatch.filter, { matchBase: true });
+    const aliases = this.aliases;
+    const names = _.keys(aliases);
+    const matcher = _.partialRight(minimatch.filter, { matchBase: true });
 
     return _.chain(patterns)
     .map(function (pattern) {
diff --git a/src/ui/appEntryTemplate.js b/src/ui/appEntryTemplate.js
index 714de7ba07fce..99a04121005bb 100644
--- a/src/ui/appEntryTemplate.js
+++ b/src/ui/appEntryTemplate.js
@@ -1,10 +1,10 @@
 module.exports = function ({env, bundle}) {
 
-  let pluginSlug = env.pluginInfo.sort()
+  const pluginSlug = env.pluginInfo.sort()
   .map(p => ' *  - ' + p)
   .join('\n');
 
-  let requires = bundle.modules
+  const requires = bundle.modules
   .map(m => `require('${m}');`)
   .join('\n');
 
diff --git a/src/ui/autoload.js b/src/ui/autoload.js
index 79ee476fd67b1..82bf7a18dc86a 100644
--- a/src/ui/autoload.js
+++ b/src/ui/autoload.js
@@ -1,30 +1,30 @@
-var _ = require('lodash');
-var resolve = require('path').resolve;
-var basename = require('path').basename;
-var readdir = require('fs').readdirSync;
+const _ = require('lodash');
+const resolve = require('path').resolve;
+const basename = require('path').basename;
+const readdir = require('fs').readdirSync;
 
-var utils = require('requirefrom')('src/utils');
-var fromRoot = utils('fromRoot');
+const utils = require('requirefrom')('src/utils');
+const fromRoot = utils('fromRoot');
 
 function scan(type) {
-  var dir = fromRoot('src/ui/public', type);
+  const dir = fromRoot('src/ui/public', type);
 
   return _.chain(readdir(dir))
   .reject(function (name) {
     return name[0] === '.' || name[0] === '_';
   })
   .map(function (filename) {
-    var path = resolve(dir, filename);
-    var name = basename(filename, '.js');
+    const path = resolve(dir, filename);
+    const name = basename(filename, '.js');
     return `ui/${type}/${name}`;
   })
   .value();
 }
 
 function findStyles() {
-  var base = ['ui/styles/theme.less', 'ui/styles/base.less'];
-  var exclude = ['ui/styles/mixins.less', 'ui/styles/variables.less'];
-  var found = scan('styles', true);
+  const base = ['ui/styles/theme.less', 'ui/styles/base.less'];
+  const exclude = ['ui/styles/mixins.less', 'ui/styles/variables.less'];
+  const found = scan('styles', true);
 
   return _.difference(_.union(base, found), exclude);
 }
diff --git a/src/ui/index.js b/src/ui/index.js
index a376e229a5d20..ebefd439077ab 100644
--- a/src/ui/index.js
+++ b/src/ui/index.js
@@ -1,22 +1,22 @@
 module.exports = async (kbnServer, server, config) => {
   let { defaults } = require('lodash');
-  let Boom = require('boom');
-  let formatUrl = require('url').format;
+  const Boom = require('boom');
+  const formatUrl = require('url').format;
   let { resolve } = require('path');
-  let readFile = require('fs').readFileSync;
+  const readFile = require('fs').readFileSync;
 
-  let fromRoot = require('../utils/fromRoot');
-  let UiExports = require('./UiExports');
-  let UiBundle = require('./UiBundle');
-  let UiBundleCollection = require('./UiBundleCollection');
-  let UiBundlerEnv = require('./UiBundlerEnv');
-  let loadingGif = readFile(fromRoot('src/ui/public/loading.gif'), { encoding: 'base64'});
+  const fromRoot = require('../utils/fromRoot');
+  const UiExports = require('./UiExports');
+  const UiBundle = require('./UiBundle');
+  const UiBundleCollection = require('./UiBundleCollection');
+  const UiBundlerEnv = require('./UiBundlerEnv');
+  const loadingGif = readFile(fromRoot('src/ui/public/loading.gif'), { encoding: 'base64'});
 
-  let uiExports = kbnServer.uiExports = new UiExports({
+  const uiExports = kbnServer.uiExports = new UiExports({
     urlBasePath: config.get('server.basePath')
   });
 
-  let bundlerEnv = new UiBundlerEnv(config.get('optimize.bundleDir'));
+  const bundlerEnv = new UiBundlerEnv(config.get('optimize.bundleDir'));
   bundlerEnv.addContext('env', config.get('env.name'));
   bundlerEnv.addContext('urlBasePath', config.get('server.basePath'));
   bundlerEnv.addContext('sourceMaps', config.get('optimize.sourceMaps'));
@@ -28,14 +28,14 @@ module.exports = async (kbnServer, server, config) => {
     uiExports.consumePlugin(plugin);
   }
 
-  let bundles = kbnServer.bundles = new UiBundleCollection(bundlerEnv, config.get('optimize.bundleFilter'));
+  const bundles = kbnServer.bundles = new UiBundleCollection(bundlerEnv, config.get('optimize.bundleFilter'));
 
   for (let app of uiExports.getAllApps()) {
     bundles.addApp(app);
   }
 
   for (let gen of uiExports.getBundleProviders()) {
-    let bundle = await gen(UiBundle, bundlerEnv, uiExports.getAllApps());
+    const bundle = await gen(UiBundle, bundlerEnv, uiExports.getAllApps());
     if (bundle) bundles.add(bundle);
   }
 
@@ -47,8 +47,8 @@ module.exports = async (kbnServer, server, config) => {
     path: '/app/{id}',
     method: 'GET',
     handler: function (req, reply) {
-      let id = req.params.id;
-      let app = uiExports.apps.byId[id];
+      const id = req.params.id;
+      const app = uiExports.apps.byId[id];
       if (!app) return reply(Boom.notFound('Unknown app ' + id));
 
       if (kbnServer.status.isGreen()) {