diff --git a/lib/user.js b/lib/user.js
index af102f459d..d070bfac22 100644
--- a/lib/user.js
+++ b/lib/user.js
@@ -1,11 +1,17 @@
 'use strict';
 
 const gravatar = require('gravatar');
-const assert = require('assert');
+const Joi = require('joi');
 
 module.exports = class User {
     constructor({ name, email, imageUrl } = {}) {
-        assert(email, 'Email is required');
+        Joi.assert(
+            email,
+            Joi.string()
+                .email()
+                .required(),
+            'Email'
+        );
         this.email = email;
         this.name = name;
         this.imageUrl =
diff --git a/lib/user.test.js b/lib/user.test.js
index 7f356bc932..5f1c45bd6f 100644
--- a/lib/user.test.js
+++ b/lib/user.test.js
@@ -18,7 +18,7 @@ test('should require email', t => {
         const user = new User(); // eslint-disable-line
     }, Error);
 
-    t.is(error.message, 'Email is required');
+    t.is(error.message, 'Email "value" is required');
 });
 
 test('Should create user with only email defined', t => {
diff --git a/package.json b/package.json
index 752f2295e5..5e725bc6d6 100644
--- a/package.json
+++ b/package.json
@@ -56,7 +56,6 @@
     ]
   },
   "dependencies": {
-    "assert": "^1.4.1",
     "async": "^2.1.5",
     "body-parser": "^1.18.2",
     "commander": "^2.9.0",
diff --git a/yarn.lock b/yarn.lock
index b44c7d7d82..979e72ac56 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -298,12 +298,6 @@ assert-plus@^0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/assert-plus/-/assert-plus-0.2.0.tgz#d74e1b87e7affc0db8aadb7021f3fe48101ab234"
 
-assert@^1.4.1:
-  version "1.4.1"
-  resolved "https://registry.yarnpkg.com/assert/-/assert-1.4.1.tgz#99912d591836b5a6f5b345c0f07eefc08fc65d91"
-  dependencies:
-    util "0.10.3"
-
 ast-types@0.x.x:
   version "0.9.14"
   resolved "https://registry.yarnpkg.com/ast-types/-/ast-types-0.9.14.tgz#d34ba5dffb9d15a44351fd2a9d82e4ab2838b5ba"
@@ -2690,10 +2684,6 @@ inherits@2, inherits@2.0.3, inherits@^2.0.1, inherits@^2.0.3, inherits@~2.0.0, i
   version "2.0.3"
   resolved "https://registry.yarnpkg.com/inherits/-/inherits-2.0.3.tgz#633c2c83e3da42a502f52466022480f4208261de"
 
-inherits@2.0.1:
-  version "2.0.1"
-  resolved "https://registry.yarnpkg.com/inherits/-/inherits-2.0.1.tgz#b17d08d326b4423e568eff719f91b0b1cbdf69f1"
-
 ini@^1.3.4, ini@~1.3.0:
   version "1.3.4"
   resolved "https://registry.yarnpkg.com/ini/-/ini-1.3.4.tgz#0537cb79daf59b59a1a517dff706c86ec039162e"
@@ -5838,12 +5828,6 @@ util-deprecate@~1.0.1:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/util-deprecate/-/util-deprecate-1.0.2.tgz#450d4dc9fa70de732762fbd2d4a28981419a0ccf"
 
-util@0.10.3:
-  version "0.10.3"
-  resolved "https://registry.yarnpkg.com/util/-/util-0.10.3.tgz#7afb1afe50805246489e3db7fe0ed379336ac0f9"
-  dependencies:
-    inherits "2.0.1"
-
 utile@0.3.x:
   version "0.3.0"
   resolved "https://registry.yarnpkg.com/utile/-/utile-0.3.0.tgz#1352c340eb820e4d8ddba039a4fbfaa32ed4ef3a"