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
    };
  }
}