How It Works

// Pseudo-code illustration
const blockChecks = Promise.race([
  checkSyntax(),
  checkDisposable(),
  checkMX()
]);

// Returns immediately on first failure
// Or waits for all to succeed

// Pseudo-code illustration
const flagChecks = await Promise.all([
  checkSMTP(),
  checkCatchall(),
  checkRoleEmail(),
  checkAlias(),
  checkDeviceFingerprint(),
  checkIPReputation()
]);

// Waits for all checks to complete

function determineRecommendation(result: ValidationResponse) {
  // Check if validation succeeded
  if (!result.success || !result.data) {
    return 'block'; // Failed validation
  }

  const { checks } = result.data;

  // Any critical check fails = BLOCK
  if (!checks.syntax?.pass) {
    return 'block'; // Invalid syntax
  }

  if (!checks.disposable?.pass) {
    return 'block'; // Disposable email
  }

  if (!checks.mx?.pass) {
    return 'block'; // No mail servers
  }

  // Apply whitelist/blacklist
  if (isWhitelisted(email)) return 'allow';
  if (isBlacklisted(email)) return 'block';

  // Count failed checks
  const failedChecks = Object.values(checks).filter(
    check => !check.pass
  ).length;

  if (failedChecks >= threshold) {
    return 'flag'; // Review recommended
  }

  return 'allow';
}

// Emails are encrypted before storage
const encrypted = await encrypt(email, projectKey);

// SHA-256 hash for indexing
const hash = sha256(email);

// Store both
await db.insert({
  email_hash: hash,
  email_encrypted: encrypted,
  signals: validationResults
});