How HeroBounce Works

Our 6-layer verification engine combines SMTP validation, AI-powered catch-all detection, and domain intelligence to deliver industry-leading accuracy.

Our 6-Layer Verification Engine

Each email goes through 20+ verification steps across 6 distinct layers

Layer 1: Syntax Validation

Instant

We validate the email format against RFC 5321 compliance, check for common typos, and identify obviously invalid patterns.

What we check:
  • • Valid character set (a-z, 0-9, special chars)
  • • Proper @ symbol placement
  • • Domain structure validity
  • • Common typo patterns
Result:
  • • ✅ Valid syntax → Continue to Layer 2
  • • ❌ Invalid syntax → Mark as INVALID

Layer 2: DNS & MX Validation

Fast

We verify the domain exists, has valid MX (Mail Exchange) records, and check SPF/DMARC configurations for security posture.

What we check:
  • • Domain DNS resolution
  • • MX record existence & priority
  • • SPF record detection
  • • DMARC policy verification
Result:
  • • ✅ Domain configured → Continue to Layer 3
  • • ❌ No MX records → Mark as INVALID

Layer 3: SMTP Handshake

Core Check

We connect to the mail server via SMTP and verify the mailbox exists without sending any actual emails. This is the most critical validation layer.

What we check:
  • • SMTP server connectivity
  • • RCPT TO: mailbox verification
  • • Server response codes (250, 550, etc.)
  • • Greylisting detection
Result:
  • • ✅ 250 OK → Mailbox exists
  • • ❌ 550 User not found → INVALID
  • • ⚠️ Accept-all response → Continue to Layer 4

Layer 4: Catch-All Detection

Our Secret Sauce

The biggest differentiator. When a domain accepts all addresses (catch-all), we don't just mark it "unknown" like competitors. Our proprietary AI analyzes multiple signals to verify individual addresses with 95%+ accuracy.

How it works:
  • • Proprietary multi-signal analysis
  • • AI-powered pattern recognition
  • • Real-time domain intelligence
  • • Continuous learning from validations
Result:
  • • Confidence score: 0-100%
  • • Clear VALID/INVALID/RISKY status
  • • No more "unknown" results
  • • Actionable data for every email

Why this matters: 30-50% of B2B emails are on catch-all domains. Competitors mark these as "unknown" and you lose the opportunity. We give you a real answer with confidence scoring.

Layer 5: Domain Intelligence

Risk Analysis

We analyze domain reputation, detect risky email types, and identify email provider characteristics to give you a complete picture.

What we detect:
  • • Disposable/temporary emails
  • • Role-based accounts (info@, support@)
  • • Email provider type
  • • Domain reputation signals
Result:
  • • Risk flags in response metadata
  • • Provider identification
  • • Confidence adjustments

Layer 6: AI Enhancement

All Paid Plans

Our AI layer applies machine learning trained on millions of validations to boost accuracy on difficult cases. Enabled by default on all paid plans.

What it does:
  • • Analyzes edge cases
  • • Boosts confidence accuracy
  • • Reduces false positives
  • • Learns from new patterns
Result:
  • • Higher overall accuracy
  • • Fewer "risky" classifications
  • • Better deliverability outcomes

Final Validation Result

After all 6 layers (over 30 validation steps/modules), you get a comprehensive validation response

{
  "email": "john.doe@company.com",
  "status": "valid",
  "is_valid": true,
  "confidence": 0.95,

  "details": {
    "syntax_valid": true,
    "dns_valid": true,
    "smtp_valid": true,
    "is_disposable": false,
    "is_role_based": false,
    "provider": "Google Workspace",
    "mx_records": 5,
    "has_spf": true,
    "has_dmarc": true
  },

  "catchall": {
    "is_catchall": true,
    "confidence": 0.92,
    "pattern_score": 0.88,
    "resolved": true
  },

  "ai_enhancement": {
    "used": true,
    "method": "hybrid"
  },

  "performance": {
    "response_time_ms": 487
  }
}

See It In Action

Start verifying emails with our 6-layer engine. Get 100 free credits to try it yourself.

14-day free trial • 100 free validations • No credit card required