diff --git a/src/models/nostrEvent.ts b/src/models/nostrEvent.ts
index 351ca36..201c6ec 100644
--- a/src/models/nostrEvent.ts
+++ b/src/models/nostrEvent.ts
@@ -7,6 +7,6 @@ export class NostrEvent {
     public kind: number, // event type, e.g., review, article, comment
     public tags: string[][], // array of keywords or hashtags
     public content: string, // text content of the event
-    public id?: ObjectId
+    public id?: ObjectId // database object id
   ) {}
 }
diff --git a/src/models/user.ts b/src/models/user.ts
index 93fe1ca..d25245b 100644
--- a/src/models/user.ts
+++ b/src/models/user.ts
@@ -3,9 +3,9 @@ import { UserRole } from '../types'
 
 export class User {
   constructor(
-    public name: string,
-    public npub: string | string[],
-    public role: UserRole,
-    public id?: ObjectId
+    public name: string, // name
+    public npub: string, // npub
+    public role: UserRole, // user role (user, reviewer, producer)
+    public id?: ObjectId // database object id
   ) {}
 }
diff --git a/src/models/wine.ts b/src/models/wine.ts
index 1bc19cb..4a1ab9c 100644
--- a/src/models/wine.ts
+++ b/src/models/wine.ts
@@ -22,8 +22,8 @@ export class Wine {
     public viticulture: Viticulture, // two-letter country codes
     public sulfites: number, // parts per million
     public filtered: boolean, // is wine filtered (fined (egg or fish))
-    public vegan: boolean,
-    public kosher: boolean,
+    public vegan: boolean, // if wine is vegan
+    public kosher: boolean, // if wine is kosher
     public closure: BottleClosure, // cork, crown-seal, screwcap
     public RRPamount: number, // 20
     public RRPcurrency: CurrencyCode, // USD
diff --git a/src/routes/coffee.router.ts b/src/routes/coffee.router.ts
index 9cfa014..acbc9e6 100644
--- a/src/routes/coffee.router.ts
+++ b/src/routes/coffee.router.ts
@@ -2,7 +2,6 @@ import express, { Request, Response } from 'express'
 import { collections } from '../services/database.service'
 import { Coffee } from '../models'
 
-// Global Config
 export const coffeeRouter = express.Router()
 
 coffeeRouter.use(express.json())
diff --git a/src/routes/nostr.router.ts b/src/routes/nostr.router.ts
index c30e5a5..ede0f06 100644
--- a/src/routes/nostr.router.ts
+++ b/src/routes/nostr.router.ts
@@ -1,4 +1,3 @@
-// External Dependencies
 import express, { Request, Response } from 'express'
 import { collections } from '../services/database.service'
 import { NostrEvent } from '../models'
@@ -10,7 +9,6 @@ import {
 import { Event } from 'nostr-tools'
 import Joi from 'joi'
 
-// Global Config
 export const nostrRouter = express.Router()
 
 nostrRouter.use(express.json())
diff --git a/src/routes/reviews.router.ts b/src/routes/reviews.router.ts
index 02fa1b9..91becfb 100644
--- a/src/routes/reviews.router.ts
+++ b/src/routes/reviews.router.ts
@@ -4,7 +4,6 @@ import { Review } from '../models'
 import { reviewValidation, handleReqError, handleReqSuccess } from '../utils'
 import Joi from 'joi'
 
-// Global Config
 export const reviewsRouter = express.Router()
 
 reviewsRouter.use(express.json())
diff --git a/src/routes/sake.router.ts b/src/routes/sake.router.ts
index 4bdda38..42a24e4 100644
--- a/src/routes/sake.router.ts
+++ b/src/routes/sake.router.ts
@@ -2,7 +2,6 @@ import express, { Request, Response } from 'express'
 import { collections } from '../services/database.service'
 import { Sake } from '../models'
 
-// Global Config
 export const sakeRouter = express.Router()
 
 sakeRouter.use(express.json())
diff --git a/src/routes/spirits.router.ts b/src/routes/spirits.router.ts
index 6904a61..d0b1246 100644
--- a/src/routes/spirits.router.ts
+++ b/src/routes/spirits.router.ts
@@ -2,7 +2,6 @@ import express, { Request, Response } from 'express'
 import { collections } from '../services/database.service'
 import { Spirit } from '../models'
 
-// Global Config
 export const spiritsRouter = express.Router()
 
 spiritsRouter.use(express.json())
diff --git a/src/routes/users.router.ts b/src/routes/users.router.ts
index 50cdc22..75bf5fa 100644
--- a/src/routes/users.router.ts
+++ b/src/routes/users.router.ts
@@ -1,11 +1,9 @@
-// External Dependencies
 import express, { Request, Response } from 'express'
 import { collections } from '../services/database.service'
 import { User } from '../models'
 import { userValidation, handleReqError, handleReqSuccess } from '../utils'
 import Joi from 'joi'
 
-// Global Config
 export const usersRouter = express.Router()
 
 usersRouter.use(express.json())
@@ -39,22 +37,12 @@ usersRouter.post('/', async (req: Request, res: Response) => {
       throw error.details[0].message
     }
 
-    if (typeof newUser.npub === 'string') {
-      const existingUser = await collections.users?.findOne({
-        npub: newUser.npub
-      })
+    const existingUser = await collections.users?.findOne({
+      npub: newUser.npub
+    })
 
-      if (existingUser) {
-        throw new Error('user with provided "npub" exists')
-      }
-    } else {
-      for (const npub of newUser.npub) {
-        const existingUser = await collections.users?.findOne({ npub })
-
-        if (existingUser) {
-          throw new Error('user with provided "npub" exists')
-        }
-      }
+    if (existingUser) {
+      throw new Error('user with provided "npub" exists')
     }
 
     const result = await collections.users?.insertOne(newUser)
diff --git a/src/routes/wines.router.ts b/src/routes/wines.router.ts
index 7d081bf..e83e397 100644
--- a/src/routes/wines.router.ts
+++ b/src/routes/wines.router.ts
@@ -2,7 +2,6 @@ import express, { Request, Response } from 'express'
 import { collections } from '../services/database.service'
 import { Wine } from '../models'
 
-// Global Config
 export const winesRouter = express.Router()
 
 winesRouter.use(express.json())
diff --git a/src/utils/validation/user.ts b/src/utils/validation/user.ts
index ddef1f7..657364e 100644
--- a/src/utils/validation/user.ts
+++ b/src/utils/validation/user.ts
@@ -2,26 +2,21 @@ import Joi from 'joi'
 import { UserRole } from '../../types'
 import { npubToHex, validateHex } from '../nostr'
 
-const npubValidation = (value: unknown, helper: Joi.CustomHelpers<unknown>) => {
-  const hex = npubToHex(value as string)
-
-  if (!hex || !validateHex(hex)) {
-    return helper.message({
-      custom: Joi.expression('"npub" contains an invalid value')
-    })
-  }
-
-  return hex
-}
-
 export const userValidation = (data: unknown): Joi.ValidationResult =>
   Joi.object({
     name: Joi.string().required(),
-    npub: Joi.alternatives()
-      .try(
-        Joi.array().items(Joi.string().custom(npubValidation)),
-        Joi.string().custom(npubValidation)
-      )
+    npub: Joi.string()
+      .custom((value, helper) => {
+        const hex = npubToHex(value as string)
+
+        if (!hex || !validateHex(hex)) {
+          return helper.message({
+            custom: Joi.expression('"npub" contains an invalid value')
+          })
+        }
+
+        return hex
+      })
       .required(),
     role: Joi.string()
       .valid(...Object.values(UserRole))