diff --git a/.eslintrc.js b/.eslintrc.js
index e172b006..d39ef237 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -30,16 +30,6 @@ module.exports = {
 
     // we use named export in utils
     'import/prefer-default-export': 'off',
-    // disable comma-dangle in functions
-    'comma-dangle': [
-      'error',
-      {
-        arrays: 'always-multiline',
-        objects: 'always-multiline',
-        imports: 'always-multiline',
-        functions: 'never',
-      },
-    ],
     // allow `console.error` & `console.warning`
     'no-console': ['error', { allow: ['warn', 'error'] }],
     // `_id` comes from Mongo
diff --git a/package-lock.json b/package-lock.json
index 66972bf2..c367a721 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1201,6 +1201,47 @@
         "find-up": "^2.1.0"
       }
     },
+    "@hapi/address": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/@hapi/address/-/address-2.0.0.tgz",
+      "integrity": "sha512-mV6T0IYqb0xL1UALPFplXYQmR0twnXG0M6jUswpquqT2sD12BOiCiLy3EvMp/Fy7s3DZElC4/aPjEjo2jeZpvw=="
+    },
+    "@hapi/hoek": {
+      "version": "6.2.4",
+      "resolved": "https://registry.npmjs.org/@hapi/hoek/-/hoek-6.2.4.tgz",
+      "integrity": "sha512-HOJ20Kc93DkDVvjwHyHawPwPkX44sIrbXazAUDiUXaY2R9JwQGo2PhFfnQtdrsIe4igjG2fPgMra7NYw7qhy0A=="
+    },
+    "@hapi/joi": {
+      "version": "15.1.0",
+      "resolved": "https://registry.npmjs.org/@hapi/joi/-/joi-15.1.0.tgz",
+      "integrity": "sha512-n6kaRQO8S+kepUTbXL9O/UOL788Odqs38/VOfoCrATDtTvyfiO3fgjlSRaNkHabpTLgM7qru9ifqXlXbXk8SeQ==",
+      "requires": {
+        "@hapi/address": "2.x.x",
+        "@hapi/hoek": "6.x.x",
+        "@hapi/marker": "1.x.x",
+        "@hapi/topo": "3.x.x"
+      }
+    },
+    "@hapi/marker": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/@hapi/marker/-/marker-1.0.0.tgz",
+      "integrity": "sha512-JOfdekTXnJexfE8PyhZFyHvHjt81rBFSAbTIRAhF2vv/2Y1JzoKsGqxH/GpZJoF7aEfYok8JVcAHmSz1gkBieA=="
+    },
+    "@hapi/topo": {
+      "version": "3.1.2",
+      "resolved": "https://registry.npmjs.org/@hapi/topo/-/topo-3.1.2.tgz",
+      "integrity": "sha512-r+aumOqJ5QbD6aLPJWqVjMAPsx5pZKz+F5yPqXZ/WWG9JTtHbQqlzrJoknJ0iJxLj9vlXtmpSdjlkszseeG8OA==",
+      "requires": {
+        "@hapi/hoek": "8.x.x"
+      },
+      "dependencies": {
+        "@hapi/hoek": {
+          "version": "8.1.0",
+          "resolved": "https://registry.npmjs.org/@hapi/hoek/-/hoek-8.1.0.tgz",
+          "integrity": "sha512-b1J4jxYnW+n6lC91V6Pqg9imP9BZq0HNCeM+3sbXg05rQsE9cGYrKFpZjyztVesGmNRE6R+QaEoWGATeIiUVjA=="
+        }
+      }
+    },
     "@marionebl/sander": {
       "version": "0.6.1",
       "resolved": "https://registry.npmjs.org/@marionebl/sander/-/sander-0.6.1.tgz",
@@ -7992,6 +8033,15 @@
       "resolved": "https://registry.npmjs.org/joi-objectid/-/joi-objectid-2.0.0.tgz",
       "integrity": "sha1-VlSVc6Zrp5Xc9rniJt5fOy027Do="
     },
+    "joigoose": {
+      "version": "4.0.8",
+      "resolved": "https://registry.npmjs.org/joigoose/-/joigoose-4.0.8.tgz",
+      "integrity": "sha512-FVid0+nWGVLKottxrjq8HlVzW4AAnu+9bq/E34LTQjzGRUcyaw63xSVf1UXeRqdlYoMG8WOipkBLQAvr42LPsA==",
+      "requires": {
+        "@hapi/hoek": "^6.2.1",
+        "@hapi/joi": "^15.0.0"
+      }
+    },
     "js-levenshtein": {
       "version": "1.1.6",
       "resolved": "https://registry.npmjs.org/js-levenshtein/-/js-levenshtein-1.1.6.tgz",
diff --git a/package.json b/package.json
index 91219bb6..1d05f1d4 100644
--- a/package.json
+++ b/package.json
@@ -40,6 +40,7 @@
     "http-status-codes": "^1.3.0",
     "joi": "^14.3.1",
     "joi-objectid": "^2.0.0",
+    "joigoose": "^4.0.8",
     "lodash": "^4.17.15",
     "mailchimp-api-v3": "^1.12.1",
     "md5": "^2.2.1",
diff --git a/src/api/article/controller.js b/src/api/article/controller.js
index 461a0b36..b3a3f574 100644
--- a/src/api/article/controller.js
+++ b/src/api/article/controller.js
@@ -149,7 +149,7 @@ export const update = async ({ params: { slugOrId }, body, user }, res, next) =>
               locale,
               articleId,
             },
-            mergeWithUpdateMetadata(localeData, user._id),
+            mergeWithUpdateMetadata(localeData, user),
             { new: true }
           )
             // unless found, create a new one.
@@ -174,7 +174,7 @@ export const update = async ({ params: { slugOrId }, body, user }, res, next) =>
       localesToUpdate.map(_id =>
         LocalizedArticle.findOneAndUpdate(
           { _id },
-          mergeWithUpdateMetadata({ active: false }, user._id)
+          mergeWithUpdateMetadata({ active: false }, user)
         ).catch(next)
       )
     );
@@ -207,7 +207,7 @@ export const update = async ({ params: { slugOrId }, body, user }, res, next) =>
 export const remove = ({ params: { slugOrId }, user }, res, next) =>
   retrieveArticleId(slugOrId, { active: true })
     .then(articleId =>
-      Article.updateOne({ _id: articleId }, mergeWithUpdateMetadata({ active: false }, user._id))
+      Article.updateOne({ _id: articleId }, mergeWithUpdateMetadata({ active: false }, user))
     )
     .then(() => res.sendStatus(HttpStatus.OK))
     .catch(next);
diff --git a/src/api/article/localized/controller.js b/src/api/article/localized/controller.js
index 4ddc4161..2424ef9c 100644
--- a/src/api/article/localized/controller.js
+++ b/src/api/article/localized/controller.js
@@ -35,7 +35,7 @@ export const create = async ({ params: { articleId }, user, body }, res, next) =
 };
 
 export const update = ({ params: { slug }, user, body }, res, next) =>
-  LocalizedArticle.findOneAndUpdate({ slug }, mergeWithUpdateMetadata(body, user._id), {
+  LocalizedArticle.findOneAndUpdate({ slug }, mergeWithUpdateMetadata(body, user), {
     new: true,
   })
     .then(checkIsFound)
diff --git a/src/api/helpers/metadata/index.js b/src/api/helpers/metadata/index.js
index 4d6641ff..48034d66 100644
--- a/src/api/helpers/metadata/index.js
+++ b/src/api/helpers/metadata/index.js
@@ -3,6 +3,13 @@ import {
   getInitObjectMetadata,
   updateObjectMetadata,
   mergeWithUpdateMetadata,
+  joiMetadataSchema,
 } from './model';
 
-export { ObjectMetadata, getInitObjectMetadata, updateObjectMetadata, mergeWithUpdateMetadata };
+export {
+  ObjectMetadata,
+  getInitObjectMetadata,
+  updateObjectMetadata,
+  mergeWithUpdateMetadata,
+  joiMetadataSchema,
+};
diff --git a/src/api/helpers/metadata/model.js b/src/api/helpers/metadata/model.js
index e67997d0..46c83c6b 100644
--- a/src/api/helpers/metadata/model.js
+++ b/src/api/helpers/metadata/model.js
@@ -1,48 +1,36 @@
 import mongoose from 'mongoose';
 
-const { Schema } = mongoose;
+import { Joi, joiToMongoose, joiSchemas } from 'validation';
 
-// ObjectMetadataSchema model is a general-purpose object to be used across the project.
-const ObjectMetadataSchema = new Schema({
-  createdAt: {
-    type: Date,
-    required: true,
-  },
-  createdBy: {
-    type: Schema.Types.ObjectId,
-    ref: 'User',
-    required: true,
-  },
-  updatedAt: {
-    type: Date,
-    required: true,
-  },
-  updatedBy: {
-    type: Schema.Types.ObjectId,
-    ref: 'User',
-    required: true,
-  },
+export const joiMetadataSchema = Joi.object({
+  createdAt: Joi.date().required(),
+  updatedAt: Joi.date().required(),
+  createdBy: joiSchemas.userRef.required(),
+  updatedBy: joiSchemas.userRef.required(),
 });
 
+// ObjectMetadataSchema model is a general-purpose object to be used across the project.
+const ObjectMetadataSchema = joiToMongoose(joiMetadataSchema);
+
 export const ObjectMetadata = mongoose.model('ObjectMetadata', ObjectMetadataSchema);
 
-export const getInitObjectMetadata = userId => ({
+export const getInitObjectMetadata = ({ _id }) => ({
   createdAt: Date.now(),
-  createdBy: userId,
+  createdBy: _id,
   updatedAt: Date.now(),
-  updatedBy: userId,
+  updatedBy: _id,
 });
 
-export const updateObjectMetadata = (oldMetadata, userId) => ({
+export const updateObjectMetadata = (oldMetadata, { _id }) => ({
   ...oldMetadata,
   updatedAt: Date.now(),
-  updatedBy: userId,
+  updatedBy: _id,
 });
 
-export const mergeWithUpdateMetadata = (data, userId) => ({
+export const mergeWithUpdateMetadata = (data, { _id }) => ({
   $set: {
     ...data,
-    'metadata.updatedBy': userId,
+    'metadata.updatedBy': _id,
     'metadata.updatedAt': Date.now(),
   },
 });
diff --git a/src/api/storage/model.js b/src/api/storage/model.js
index abb6f8bd..be7d18b3 100644
--- a/src/api/storage/model.js
+++ b/src/api/storage/model.js
@@ -1,41 +1,31 @@
 import mongoose from 'mongoose';
 
 import {
-  ObjectMetadata,
+  joiMetadataSchema,
   getInitObjectMetadata,
   mergeWithUpdateMetadata,
 } from 'api/helpers/metadata';
+import { Joi, joiToMongoose } from 'validation';
 
-const { Schema } = mongoose;
-
-const StorageEntitySchema = new Schema({
-  key: {
-    type: String,
-    required: true,
-    unique: true,
-  },
-  document: {
-    type: Schema.Types.Mixed,
-    required: true,
-  },
-  accessPolicy: {
-    type: String,
-    enum: ['public'],
-    default: 'public',
-    required: true,
-  },
-  metadata: {
-    type: ObjectMetadata.schema,
-    required: true,
-  },
+const joiStorageEntitySchema = Joi.object({
+  key: Joi.string()
+    .required()
+    .meta({ unique: true }),
+  document: Joi.object().required(),
+  accessPolicy: Joi.string()
+    .valid('public')
+    .default('public'),
+  metadata: joiMetadataSchema.required(),
 });
 
+const StorageEntitySchema = joiToMongoose(joiStorageEntitySchema);
+
 StorageEntitySchema.statics.getValue = function(key) {
   return this.findOne({ key });
 };
 
-StorageEntitySchema.statics.setValue = function(key, value, userId) {
-  return this.findOneAndUpdate({ key }, mergeWithUpdateMetadata({ document: value }, userId), {
+StorageEntitySchema.statics.setValue = function(key, value, _id) {
+  return this.findOneAndUpdate({ key }, mergeWithUpdateMetadata({ document: value }, { _id }), {
     new: true,
   }).then(
     entity =>
@@ -43,7 +33,7 @@ StorageEntitySchema.statics.setValue = function(key, value, userId) {
       this({
         key,
         document: value,
-        metadata: getInitObjectMetadata(userId),
+        metadata: getInitObjectMetadata({ _id }),
       }).save()
   );
 };
diff --git a/src/api/tag/model.js b/src/api/tag/model.js
index deb9c944..92ad4f6d 100644
--- a/src/api/tag/model.js
+++ b/src/api/tag/model.js
@@ -1,37 +1,26 @@
 import mongoose from 'mongoose';
 import set from 'lodash/set';
 
-import Joi from 'joi';
-
-import { ObjectMetadata } from 'api/helpers/metadata';
+import { joiMetadataSchema } from 'api/helpers/metadata';
 import { Topic } from 'api/topic';
 import { TAG_CONTENT_SCHEMA } from 'constants/topic';
 import { ValidationError } from 'utils/validation';
-
-const { Schema } = mongoose;
-
-const TagSchema = new Schema({
-  topic: {
-    type: Schema.Types.ObjectId,
-    ref: 'Topic',
-    required: true,
-  },
-  slug: {
-    type: String,
-    required: true,
-    unique: true,
-  },
-  content: {
-    // Content depends on which Topic this Tag belongs to.
-    type: Schema.Types.Mixed,
-    required: true,
-  },
-  metadata: {
-    type: ObjectMetadata.schema,
-    required: true,
-  },
+import { Joi, joiToMongoose } from 'validation';
+
+const joiTagSchema = Joi.object({
+  topic: Joi.string()
+    .meta({ type: 'ObjectId', ref: 'Topic' })
+    .required(),
+  slug: Joi.string()
+    .required()
+    .meta({ unique: true }),
+  // content depends on which `Topic` this `Tag` belongs to.
+  content: Joi.object().required(),
+  metadata: joiMetadataSchema.required(),
 });
 
+const TagSchema = joiToMongoose(joiTagSchema);
+
 TagSchema.pre('validate', async function(next) {
   const topic = await Topic.findOne({ _id: this.topic });
 
diff --git a/src/api/topic/model.js b/src/api/topic/model.js
index bf7be01d..6be223c1 100644
--- a/src/api/topic/model.js
+++ b/src/api/topic/model.js
@@ -1,23 +1,19 @@
 import mongoose from 'mongoose';
 
-import { ObjectMetadata } from 'api/helpers/metadata';
+import { joiMetadataSchema } from 'api/helpers/metadata';
+import { Joi, joiToMongoose } from 'validation';
 import { TOPIC_SLUGS } from 'constants/topic';
 
-const { Schema } = mongoose;
-
-const TopicSchema = new Schema({
-  slug: {
-    type: String,
-    required: true,
-    unique: true,
-    enum: TOPIC_SLUGS,
-  },
-  metadata: {
-    type: ObjectMetadata.schema,
-    required: true,
-  },
+const joiTopicSchema = Joi.object({
+  slug: Joi.string()
+    .valid(TOPIC_SLUGS)
+    .required()
+    .meta({ unique: true }),
+  metadata: joiMetadataSchema.required(),
 });
 
+const TopicSchema = joiToMongoose(joiTopicSchema);
+
 TopicSchema.statics.getAll = function() {
   return this.find().select('slug');
 };
diff --git a/src/constants/storage.js b/src/constants/storage.js
index 6dfdbb28..f91dbea4 100644
--- a/src/constants/storage.js
+++ b/src/constants/storage.js
@@ -1,22 +1,16 @@
-import Joi from 'joi';
-import joiObjectId from 'joi-objectid';
-
-Joi.objectId = joiObjectId(Joi);
-
-const DATA_SCHEMA = entities =>
-  Joi.object().pattern(Joi.string().valid(entities), Joi.array().items(Joi.objectId()));
+import { Joi } from 'validation';
 
 export const MAIN_PAGE_KEY = 'main-page-key';
+export const SIDEBAR_KEY = 'sidebar-key';
 
 // This is a list of Main Page Entities to be accepted by setMainPage() method.
 // Note: 'topics' are not accepted; get method always returns all topics available.
 // TODO: to add 'banners', 'diary'.
 const MAIN_PAGE_ENTITIES = ['articles', 'tags'];
-
-export const MAIN_PAGE_DATA_SCHEMA = DATA_SCHEMA(MAIN_PAGE_ENTITIES);
-
-export const SIDEBAR_KEY = 'sidebar-key';
-
 const SIDEBAR_ENTITIES = ['tags'];
 
-export const SIDEBAR_DATA_SCHEMA = DATA_SCHEMA(SIDEBAR_ENTITIES);
+const getDataSchema = entities =>
+  Joi.object().pattern(Joi.string().valid(entities), Joi.array().items(Joi.objectId()));
+
+export const joiMainPageDataSchema = getDataSchema(MAIN_PAGE_ENTITIES);
+export const joiSidebarDataSchema = getDataSchema(SIDEBAR_ENTITIES);
diff --git a/src/constants/topic.js b/src/constants/topic.js
index 9babbcd6..08aa70b4 100644
--- a/src/constants/topic.js
+++ b/src/constants/topic.js
@@ -1,43 +1,36 @@
-import Joi from 'joi';
+import { Joi, joiSchemas } from 'validation';
 
-const LOCALIZED_TEXT_SCHEMA_BE_REQUIRED = Joi.object().keys({
-  be: Joi.string().required(),
-  en: Joi.string(),
-  ru: Joi.string(),
-});
-
-// Tag Content Schemas must be consistent with the data in our Google Spreadsheet.
 export const TAG_CONTENT_SCHEMA = {
-  locations: Joi.object().keys({
-    title: LOCALIZED_TEXT_SCHEMA_BE_REQUIRED.required(),
+  locations: Joi.object({
+    title: joiSchemas.localizedText.required(),
     image: Joi.string().required(),
   }),
-  themes: Joi.object().keys({
-    title: LOCALIZED_TEXT_SCHEMA_BE_REQUIRED.required(),
+  themes: Joi.object({
+    title: joiSchemas.localizedText.required(),
   }),
-  personalities: Joi.object().keys({
-    name: LOCALIZED_TEXT_SCHEMA_BE_REQUIRED.required(),
-    dates: LOCALIZED_TEXT_SCHEMA_BE_REQUIRED.required(),
+  personalities: Joi.object({
+    name: joiSchemas.localizedText.required(),
+    dates: joiSchemas.localizedText.required(),
     image: Joi.string().required(),
     color: Joi.string()
       .regex(/^[0-9a-fA-F]{6}$/)
       .required(),
-    description: LOCALIZED_TEXT_SCHEMA_BE_REQUIRED.required(),
+    description: joiSchemas.localizedText.required(),
   }),
-  times: Joi.object().keys({
-    title: LOCALIZED_TEXT_SCHEMA_BE_REQUIRED,
+  times: Joi.object({
+    title: joiSchemas.localizedText,
   }),
-  brands: Joi.object().keys({
-    title: LOCALIZED_TEXT_SCHEMA_BE_REQUIRED.required(),
-    image: Joi.string().required(),
+  brands: Joi.object({
+    title: joiSchemas.localizedText.required(),
     // TODO: to improve images validation.
-  }),
-  authors: Joi.object().keys({
-    firstName: LOCALIZED_TEXT_SCHEMA_BE_REQUIRED.required(),
-    lastName: LOCALIZED_TEXT_SCHEMA_BE_REQUIRED.required(),
-    bio: LOCALIZED_TEXT_SCHEMA_BE_REQUIRED.required(),
     image: Joi.string().required(),
+  }),
+  authors: Joi.object({
+    firstName: joiSchemas.localizedText.required(),
+    lastName: joiSchemas.localizedText.required(),
+    bio: joiSchemas.localizedText.required(),
     // TODO: to improve images validation.
+    image: Joi.string().required(),
   }),
 };
 
diff --git a/src/utils/validation.js b/src/utils/validation.js
index bfd3e91c..d1305bf2 100644
--- a/src/utils/validation.js
+++ b/src/utils/validation.js
@@ -6,7 +6,7 @@ import set from 'lodash/set';
 import mongoose from 'mongoose';
 import Joi from 'joi';
 
-import { MAIN_PAGE_DATA_SCHEMA, SIDEBAR_DATA_SCHEMA } from 'constants/storage';
+import { joiMainPageDataSchema, joiSidebarDataSchema } from 'constants/storage';
 
 export function ValidationError(message) {
   return HttpError(HttpStatus.BAD_REQUEST, message);
@@ -79,14 +79,14 @@ const updateArticleValidator = ({ body }, res, next) => {
 };
 
 export const checkMainPageEntitiesFormat = data =>
-  Joi.validate(data, MAIN_PAGE_DATA_SCHEMA).error === null;
+  Joi.validate(data, joiMainPageDataSchema).error === null;
 
 const setMainPageValidator = ({ body }, res, next) => {
   const valid = checkMainPageEntitiesFormat(body.data);
   return next(!valid && new ValidationError({ mainPageEntities: 'not valid' }));
 };
 
-const checkSidebarEntitiesFormat = data => Joi.validate(data, SIDEBAR_DATA_SCHEMA).error === null;
+const checkSidebarEntitiesFormat = data => Joi.validate(data, joiSidebarDataSchema).error === null;
 
 const setSidebarValidator = ({ body }, res, next) => {
   const valid = checkSidebarEntitiesFormat(body.data);
@@ -173,6 +173,7 @@ export const permissionsObjectValidator = {
   message: 'errors.badPermissions',
 };
 
+// TODO: replace with `joiSchemas.color`
 export const colorValidator = {
   validator: v => /^[0-9a-fA-F]{6}$/.test(v),
   message: 'errors.failedMatchRegex',
diff --git a/src/validation/index.js b/src/validation/index.js
new file mode 100644
index 00000000..0b634afc
--- /dev/null
+++ b/src/validation/index.js
@@ -0,0 +1,13 @@
+import mongoose from 'mongoose';
+import Joi from 'joi';
+import joiObjectId from 'joi-objectid';
+import getJoigoose from 'joigoose';
+
+import joiSchemas from './schemas';
+
+Joi.objectId = joiObjectId(Joi);
+
+const Joigoose = getJoigoose(mongoose);
+const joiToMongoose = (model, options) => new mongoose.Schema(Joigoose.convert(model), options);
+
+export { Joi, joiToMongoose, joiSchemas };
diff --git a/src/validation/schemas.js b/src/validation/schemas.js
new file mode 100644
index 00000000..74cafbc6
--- /dev/null
+++ b/src/validation/schemas.js
@@ -0,0 +1,15 @@
+import { Joi } from './index';
+
+const schemas = {};
+
+schemas.userRef = Joi.string().meta({ type: 'ObjectId', ref: 'User' });
+
+schemas.localizedText = Joi.object({
+  be: Joi.string().required(),
+  en: Joi.string(),
+  ru: Joi.string(),
+});
+
+schemas.color = Joi.string().regex(/^[0-9a-fA-F]{6}$/);
+
+export default schemas;