Email Validation Best Practices

Multi-Layer Validation Architecture

Implementation Code Example

// Production-ready email validation implementation
class EmailValidator {
 constructor(apiKey) {
 this.apiKey = apiKey;
 this.cache = new Map();
 this.rateLimit = new RateLimit(100, 60000); // 100 requests per minute
 }

 async validateEmail(email, options = {}) {
 try {
 // Step 1: Basic syntax validation
 if (!this.isValidSyntax(email)) {
 return { valid: false, reason:'Invalid syntax', confidence: 1.0 };
 }

 // Step 2: Check cache
 const cached = this.cache.get(email);
 if (cached && !this.isCacheExpired(cached)) {
 return cached.result;
 }

 // Step 3: Rate limiting
 if (!this.rateLimit.check()) {
 throw new Error('Rate limit exceeded');
 }

 // Step 4: API validation with retry logic
 const result = await this.apiValidation(email, options);

 // Step 5: Cache result
 this.cache.set(email, {
 result,
 timestamp: Date.now(),
 ttl: options.cacheTTL || 3600000 // 1 hour default
 });

 return result;

 } catch (error) {
 return this.handleError(error, email);
 }
 }

 async apiValidation(email, options) {
 const params = new URLSearchParams({
 email: email,
 verifyMx: options.checkDisposable ?? true,
 verifySmtp: true,
 detectName: options.provideSuggestions ?? true,
 suggestDomain: options.provideSuggestions ?? true,
 checkDomainAge: true,
 checkDomainRegistration: true
 });

 const response = await fetch(`https://api.email-check.app/v1-get-email-details?${params}`, {
 headers: {
'accept':'application/json',
'x-api-key': this.apiKey
 }
 });

 if (!response.ok) {
 throw new Error(`API error: ${response.status}`);
 }

 return await response.json();
 }

 handleError(error, email) {
 console.error('Email validation error:', error);

 // Graceful degradation - fall back to basic validation
 return {
 valid: this.isValidSyntax(email),
 reason:'API unavailable - basic validation only',
 confidence: 0.5,
 error: error.message
 };
 }
}