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Best Practices

Email validation delivers the best results when used as part of a continuous list hygiene and deliverability strategy, not as a one-time check. This guide outlines recommended ways to apply MX18 Email Validation across your email lifecycle.

Where to use email validation

1. During user signup

Validate email addresses at the point of signup or registration.

Why

  • Prevent fake, disposable, or mistyped emails from entering your system
  • Improve onboarding email delivery (verification, welcome emails)
  • Maintain a clean user base from day one

Recommended action

  • Block or challenge signups with suggested_action = do_not_send
  • Flag review addresses for additional verification (OTP, double opt-in)

2. Before sending campaigns

Always validate recipients before sending large transactional or promotional campaigns.

Why

  • Reduce hard bounces
  • Protect IP and domain reputation
  • Improve inbox placement across ISPs

Recommended action

  • Send only to suggested_action = send
  • Suppress do_not_send addresses

3. During list imports and migrations

Validate email lists when importing from external sources or migrating between platforms.

Why

  • Legacy lists often contain stale or invalid addresses
  • Old engagement data may not reflect current deliverability risk
  • Prevent reputation damage during ramp-up

Recommended action

  • Validate entire lists before activating them
  • Segment lists by trust band
  • Gradually reintroduce medium-confidence addresses

How to use validation results effectively

Use suggested_action as the primary control

The suggested_action field is designed to be automation-friendly.

  • send → include in normal sending flows
  • do_not_send → suppress immediately

This avoids overfitting logic around individual signals.

Treat catch-all addresses carefully

Catch-all domains (is_catch_all = true) can still be valid, but carry uncertainty.

Best practice

  • Send to catch-all addresses only if engagement history is positive
  • Avoid repeated retries to non-responsive catch-all recipients
  • Revalidate periodically

Block disposable emails early

Disposable addresses are rarely valuable and often harm engagement metrics.

Best practice

  • Block or suppress all disposable = true addresses
  • Do not include disposable emails in warm-up or onboarding flows

Validation frequency

Email validity changes over time.

Recommended cadence

  • Active users: Revalidate every 60–90 days
  • Inactive or cold lists: Revalidate before every campaign
  • Long-term databases: Schedule periodic revalidation

Avoid validating the same address repeatedly within short time windows unless necessary.

Combining validation with engagement data

Validation should complement—not replace—engagement signals.

Recommended approach

  • Use validation to determine can this email receive mail?
  • Use engagement metrics to determine should I keep sending?

Example:

  • Valid + unengaged → reduce frequency or pause
  • Valid + engaged → prioritize
  • Invalid + engaged (rare) → investigate before suppression

IP and domain warm-up considerations

When warming up new IPs or domains:

  • Use validation to build a high-confidence seed list
  • Send with only trust_band = high

This reduces early reputation risk during warm-up.

Common mistakes to avoid

  • Treating validation as a one-time cleanup
  • Sending to low-score addresses “just once”
  • Ignoring review recommendations entirely
  • Validating after sending instead of before
  • Overlooking revalidation for long-lived lists

Summary

  • Validate early and validate often
  • Automate decisions using suggested_action
  • Suppress high-risk addresses immediately
  • Combine validation with engagement and suppression logic
  • Revalidate periodically to keep lists healthy

Used correctly, email validation significantly improves deliverability, engagement, and operational efficiency.

What’s next

  • FAQ – answers to common questions and edge cases

Need help? Contact Support or visit https://support.mx18.com