diff --git a/__tests__/validation.test.ts b/__tests__/validation.test.ts
new file mode 100644
index 0000000..06c989c
--- /dev/null
+++ b/__tests__/validation.test.ts
@@ -0,0 +1,101 @@
+import mongoose from 'mongoose';
+import { isValidEmail, getEmailValidationError, createUniqueEmailValidator } from '../lib/validation';
+import User from '../models/User';
+
+describe('Email Validation', () => {
+  // Setup MongoDB connection for unique constraint tests
+  beforeAll(async () => {
+    await mongoose.connect(process.env.MONGODB_URI || 'mongodb://localhost:27017/testdb');
+  });
+
+  // Cleanup after tests
+  afterAll(async () => {
+    await mongoose.connection.close();
+  });
+
+  // Clear database before each test
+  beforeEach(async () => {
+    await User.deleteMany({});
+  });
+
+  // Comprehensive test cases for email formats
+  const validEmails = [
+    'user@example.com',
+    'firstname.lastname@example.com',
+    'user+tag@example.com',
+    'user123@example.co.uk',
+    'very.common@example.com',
+    'disposable.style.email.with+symbol@example.com',
+    'other.email-with-hyphen@example.com',
+    'user.name+tag@example.org',
+  ];
+
+  const invalidEmails = [
+    '',
+    '   ',
+    'invalid-email',
+    'user@',
+    '@example.com',
+    'user@example',
+    'user@.com',
+    'user@example.',
+    'user@example..com',
+    'a@b.c',  // Too short
+    'a' .repeat(65) + '@example.com', // Local part too long
+    'user@' + 'a'.repeat(254) + '.com', // Domain too long
+  ];
+
+  // Validate email format tests
+  describe('isValidEmail - Format Validation', () => {
+    validEmails.forEach(email => {
+      it(`should return true for valid email: ${email}`, () => {
+        expect(isValidEmail(email)).toBe(true);
+      });
+    });
+
+    invalidEmails.forEach(email => {
+      it(`should return false for invalid email: ${email}`, () => {
+        expect(isValidEmail(email)).toBe(false);
+      });
+    });
+  });
+
+  // Error message generation tests
+  describe('getEmailValidationError', () => {
+    it('should return error for empty email', () => {
+      expect(getEmailValidationError('')).toBe('Email address is required');
+      expect(getEmailValidationError('   ')).toBe('Email address is required');
+    });
+
+    it('should return error for invalid email formats', () => {
+      expect(getEmailValidationError('invalid-email')).toBe('Please enter a valid email address (e.g., example@domain.com)');
+    });
+
+    it('should return null for valid email', () => {
+      expect(getEmailValidationError('user@example.com')).toBeNull();
+    });
+  });
+
+  // Unique constraint tests
+  describe('Unique Email Constraint', () => {
+    it('should prevent duplicate email registration (case-insensitive)', async () => {
+      // Create first user
+      const user1 = new User({ email: 'test@example.com' });
+      await user1.save();
+
+      // Attempt to create user with same email (different case)
+      const user2 = new User({ email: 'TEST@EXAMPLE.COM' });
+      
+      // Expect an error about duplicate email
+      await expect(user2.save()).rejects.toThrow('Email already in use');
+    });
+
+    it('should allow unique email registration', async () => {
+      const user1 = new User({ email: 'unique1@example.com' });
+      const user2 = new User({ email: 'unique2@example.com' });
+
+      await expect(user1.save()).resolves.toBeTruthy();
+      await expect(user2.save()).resolves.toBeTruthy();
+    });
+  });
+});
\ No newline at end of file
diff --git a/lib/validation.ts b/lib/validation.ts
new file mode 100644
index 0000000..4a42fe0
--- /dev/null
+++ b/lib/validation.ts
@@ -0,0 +1,71 @@
+import mongoose from 'mongoose';
+
+/**
+ * Validates email format according to RFC 5322 standard
+ * @param email - Email address to validate
+ * @returns boolean indicating if the email is valid
+ */
+export const isValidEmail = (email: string): boolean => {
+  // Trim and convert to lowercase for consistent validation
+  if (!email) return false;
+  const trimmedEmail = email.trim().toLowerCase();
+  
+  // Comprehensive RFC 5322 email validation regex
+  const emailRegex = /^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$/;
+  
+  // Validate email format and length
+  if (
+    trimmedEmail.length < 5 || 
+    trimmedEmail.length > 254 || 
+    !emailRegex.test(trimmedEmail)
+  ) {
+    return false;
+  }
+  
+  // Additional checks for email parts
+  const [local, domain] = trimmedEmail.split('@');
+  return (
+    local.length <= 64 && 
+    domain.length <= 253 && 
+    domain.split('.').every(part => part.length <= 63)
+  );
+};
+
+/**
+ * Generates a descriptive error message for email validation
+ * @param email - Email address to validate
+ * @returns Error message or null if email is valid
+ */
+export const getEmailValidationError = (email: string): string | null => {
+  if (!email || email.trim().length === 0) {
+    return 'Email address is required';
+  }
+  
+  if (!isValidEmail(email)) {
+    return 'Please enter a valid email address (e.g., example@domain.com)';
+  }
+  
+  return null;
+};
+
+/**
+ * Creates a unique email validator for Mongoose
+ * @param model - Mongoose model to check against
+ * @returns Async validation function
+ */
+export const createUniqueEmailValidator = (model: mongoose.Model<any>) => {
+  return async function(email: string): Promise<boolean> {
+    // Validate email format first
+    if (!isValidEmail(email)) {
+      throw new Error('Invalid email format');
+    }
+    
+    // Perform case-insensitive unique check
+    const existingUser = await model.findOne({ 
+      email: { $regex: new RegExp(`^${email}$`, 'i') } 
+    });
+    
+    // Return true if no existing user found
+    return !existingUser;
+  };
+};
\ No newline at end of file
diff --git a/models/User.ts b/models/User.ts
new file mode 100644
index 0000000..900e0f7
--- /dev/null
+++ b/models/User.ts
@@ -0,0 +1,70 @@
+import mongoose from 'mongoose';
+import { isValidEmail } from '../lib/validation';
+
+// Define the User schema interface
+interface IUser extends mongoose.Document {
+  email: string;
+  createdAt: Date;
+  updatedAt: Date;
+}
+
+// Create the User schema with unique, case-insensitive email validation
+const UserSchema = new mongoose.Schema<IUser>({
+  email: {
+    type: String,
+    required: [true, 'Email is required'],
+    unique: true,
+    lowercase: true, // Store emails in lowercase
+    trim: true,
+    validate: {
+      validator: function(value: string) {
+        return isValidEmail(value);
+      },
+      message: 'Invalid email format'
+    }
+  }
+}, {
+  timestamps: true, // Automatically add createdAt and updatedAt
+  // Ensure case-insensitive unique index
+  autoIndex: true
+});
+
+// Create a pre-save middleware to ensure email uniqueness
+UserSchema.pre('save', async function(next) {
+  // Only run this check if email is modified
+  if (!this.isModified('email')) return next();
+
+  try {
+    // Check for existing user with the same email (case-insensitive)
+    const existingUser = await this.constructor.findOne({ 
+      email: this.email 
+    });
+
+    if (existingUser && existingUser._id.toString() !== this._id.toString()) {
+      next(new Error('Email already in use'));
+    } else {
+      next();
+    }
+  } catch (error) {
+    next(error as mongoose.CallbackError);
+  }
+});
+
+// Create a compound unique index for case-insensitive email
+UserSchema.index({ email: 1 }, { 
+  unique: true, 
+  collation: { locale: 'en', strength: 2 } 
+});
+
+// Ensure email is lowercase before saving
+UserSchema.pre('save', function(next) {
+  if (this.isModified('email')) {
+    this.email = this.email.toLowerCase();
+  }
+  next();
+});
+
+// Create and export the User model
+const User = mongoose.models.User || mongoose.model<IUser>('User', UserSchema);
+
+export default User;
\ No newline at end of file
diff --git a/types.d.ts b/types.d.ts
index a2748eb..c26df11 100644
--- a/types.d.ts
+++ b/types.d.ts
@@ -1,109 +1,22 @@
-/* eslint-disable no-unused-vars */
-type Job = {
-  data: [
-    {
-      employer_name: string;
-      employer_logo: string;
-      employer_website: string;
-      employer_company_type: string;
-      job_publisher: string;
-      job_id: string;
-      job_employment_type: string;
-      job_title: string;
-      job_apply_link: string;
-      job_apply_is_direct: boolean;
-      job_apply_quality_score: number;
-      job_description: string;
-      job_is_remote: boolean;
-      job_posted_at_timestamp: number;
-      job_posted_at_datetime_utc: string;
-      job_city: string;
-      job_state: string;
-      job_country: string;
-      job_latitude: number;
-      job_longitude: number;
-      job_benefits: null;
-      job_google_link: string;
-      job_offer_expiration_datetime_utc: string;
-      job_offer_expiration_timestamp: number;
-      job_required_experience: {
-        no_experience_required: boolean;
-        required_experience_in_months: null;
-        experience_mentioned: boolean;
-        experience_preferred: boolean;
-      };
-      job_required_skills: null;
-      job_required_education: {
-        postgraduate_degree: boolean;
-        professional_certification: boolean;
-        high_school: boolean;
-        associates_degree: boolean;
-        bachelors_degree: boolean;
-        degree_mentioned: boolean;
-        degree_preferred: boolean;
-        professional_certification_mentioned: boolean;
-      };
-      job_experience_in_place_of_education: boolean;
-      job_min_salary: null;
-      job_max_salary: null;
-      job_salary_currency: null;
-      job_salary_period: null;
-      job_highlights: {
-        Qualifications: [string];
-        Responsibilities: [string, string];
-        Benefits: [string, string, string];
-      };
-      job_job_title: null;
-      job_posting_language: string;
-      job_onet_soc: string;
-      job_onet_job_zone: string;
-      job_naics_code: string;
-      job_naics_name: string;
-    },
-  ];
-};
+import mongoose from 'mongoose';
 
-type JobResult = Job["data"][0];
+declare module 'mongoose' {
+  interface EmailValidationOptions {
+    message?: string;
+  }
 
-type JobSalaryEntryType = {
-  location?: string;
-  job_title?: string;
-  publisher_name?: string;
-  publisher_link?: string;
-  min_salary?: number;
-  max_salary?: number;
-  median_salary?: number;
-  salary_period?: "YEAR";
-  salary_currency?: "CAD";
-};
-interface JobRequiredExperienceType {
-  no_experience_required?: boolean;
-  required_experience_in_months: number | null;
-  experience_mentioned?: boolean;
-  experience_preferred?: boolean;
+  interface SchemaTypeOptions<T> {
+    /**
+     * Custom email validation for mongoose schemas
+     */
+    email?: boolean | EmailValidationOptions;
+  }
 }
 
-interface SearchParams {
-  query?: string;
-  searchQuery?: string;
-  employmentType?: string;
-  pageNumber?: number;
-  recommended?: boolean;
-}
-
-interface CommonFilterDataShapeType {
-  name: string;
-  value: string;
-}
-
-type CompanyDetailCardProps = {
-  logo: string;
-  employerName: string;
-  companyType: string;
-  city: string;
-  state: string;
-  companyLink: string | null;
-  jobId: string;
-  companyJobs: JobResult[];
-  country: string;
-};
+/**
+ * Email validation interface for user registration
+ */
+export interface IUserEmail {
+  email: string;
+  isValidEmail: (email: string) => boolean;
+}
\ No newline at end of file