Enrich Engine

Email verification helps you maintain list hygiene and improve deliverability. Enrich Engine offers a hybrid verification system that balances speed, accuracy, and cost.

Understanding Verification Methods

SMTP Verification (Free)

Direct communication with email servers to check if an address exists.

Pros:

Completely free
Fast (1000+ emails in minutes)
No external dependencies

Cons:

~85% accuracy
Can't verify catch-all domains
Some servers block checks

API Verification (MillionVerifier)

Third-party service with advanced verification techniques.

Pros:

~99% accuracy
Handles catch-all domains
Bypasses server blocks

Cons:

$0.0005 per email
Slower processing
External API dependency

Recommended Workflow

For most use cases, we recommend the SMTP + API Fallback method:

Start SMTP Verification

Create a verification job with smtp_api_fallback method. This runs free SMTP checks on all emails.

Review Results

When SMTP completes, check your coverage percentage. Typically you'll see 60-85% definitive results (valid or invalid), with the rest as catch-all or unknown.

Decide on Gaps

Choose whether to accept current results (free) or fill gaps using the paid API. The cost estimate endpoint shows exactly what each option will cost.

Export Clean List

Download your list with verification status for each email. Filter by valid emails only for outreach campaigns.

Cost Optimization Tips

Start with SMTP - Always run free SMTP first to identify obvious invalids
Fill unknowns only - Usually the best value; catch-alls often work fine
Batch your lists - Verify in batches to control costs
Check coverage first - If SMTP gives 80%+ coverage, you may not need API

Understanding Results

Status	Meaning	Recommendation
Valid	Mailbox exists and accepts mail	Safe to email
Invalid	Mailbox doesn't exist or domain invalid	Remove from list
Catch-All	Domain accepts all emails	Likely valid, but verify with API if important
Unknown	Verification failed (timeout, blocked)	Verify with API for certainty

Example Integration

// 1. Create verification job
const job = await fetch('/api/verification/jobs', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  credentials: 'include',
  body: JSON.stringify({
    listId: 'list_abc123',
    verificationMethod: 'smtp_api_fallback'
  })
}).then(r => r.json());

// 2. Poll for progress
const pollProgress = async () => {
  const progress = await fetch(`/api/verification/jobs/${job.id}/progress`, {
    credentials: 'include'
  }).then(r => r.json());

  if (progress.job.verificationStage === 'awaiting_decision') {
    // SMTP complete, show decision UI
    return progress;
  }

  // Still processing, poll again
  setTimeout(pollProgress, 2000);
};

// 3. Get cost estimate
const estimate = await fetch(`/api/verification/jobs/${job.id}/estimate`, {
  credentials: 'include'
}).then(r => r.json());

console.log(`Fill all gaps: $${estimate.fillAllGapsCost}`);

// 4. Submit decision
await fetch(`/api/verification/jobs/${job.id}/decision`, {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  credentials: 'include',
  body: JSON.stringify({
    decision: 'fill_unknowns_only'
  })
});

Next Steps

API Reference - Full endpoint documentation
Bulk Enrichment - Enrich emails before verification

Email Verification Guide