How to Handle Catch-All Emails Without Killing Conversion

What Are Catch-All Emails?

A catch-all (also called "accept-all") email address is one hosted on a domain where the mail server is configured to accept emails sent to any address at that domain — whether the specific mailbox exists or not.

For example, if bigcorp.com has a catch-all policy, emails to sarah@bigcorp.com,nobody@bigcorp.com, and even asdfg@bigcorp.com will all be accepted by the server. This makes it impossible for verification services to confirm whether a specific mailbox actually exists.

Why Catch-All Addresses Are a Problem

Catch-all emails create a verification blind spot. When EmailVer pings the mail serverwith an EHLO message, a catch-all server responds "yes, I'll accept that" regardless of whether the address is real. This means:

• Some catch-all addresses are real, active mailboxes owned by real people
• Others are completely fake addresses that happen to be "accepted" by the server
• You have no way to tell the difference from the verification result alone

If you include all catch-all addresses in your sends, some will bounce. If you exclude them all, you'll miss real contacts. Neither approach is ideal — so you need a smarter strategy.

How Many Catch-All Addresses Are in a Typical List?

Catch-all addresses typically make up 10–30% of a B2B email list and 3–8% of a B2C list. Corporate domains are far more likely to use catch-all policies than consumer email providers like Gmail or Yahoo.

That means blindly deleting all catch-all addresses could remove a significant chunk of your audience — including valid prospects and paying customers.

The Segmentation Strategy

Instead of a blanket include/exclude decision, segment your catch-all addresses and handle them differently based on the campaign type and your risk tolerance.

Step 1: Separate Catch-All Addresses into Their Own Segment

After running your list through email verification, create a separate segment for all addresses flagged as catch-all. Never mix them into your main verified segment — treat them as a distinct group that needs its own rules.

Step 2: Score by Engagement History

If you have historical data, split your catch-all segment further:

• Previously engaged — Has opened or clicked in the past 90 days. Safe to include in most campaigns
• Never engaged — No opens or clicks on record. Higher risk, send cautiously
• New / unknown — Recently acquired, no engagement data. Test in small batches

Step 3: Send in Small, Monitored Batches

For catch-all addresses without engagement history, send in batches of 500–1,000 and monitor bounce rates after each batch. If the bounce rate stays under 2%, you can continue expanding. If it spikes above 5%, stop and remove the remaining addresses.

Step 4: Set Automatic Suppression Rules

Configure your ESP to automatically suppress any catch-all address that hard bounces even once. Also set up soft-bounce thresholds — if a catch-all address soft-bounces twice, suppress it permanently.

When to Always Exclude Catch-All Addresses

• Cold outreach — When you're emailing people for the first time with no relationship
• Reputation recovery — If you're rebuilding sender reputation after a deliverability incident
• New IP / domain warmup — During the warmup phase, only send to confirmed valid addresses
• High-volume promotional blasts — The volume amplifies any bounce rate issues

When It's Safe to Include Catch-All Addresses

• Transactional emails — Order confirmations, password resets. These are expected and important
• Engaged subscribers — If they've opened or clicked recently, the address is clearly working
• Small, targeted sends — Low volume minimizes risk to your sender reputation
• High-value leads — When the potential value justifies the small bounce risk

The 5-Campaign Test

Here's a practical framework for deciding what to do with your catch-all segment over time:

1. Campaign 1: Send only to the "previously engaged" catch-all addresses. Track bounces
2. Campaign 2: Add the "new/unknown" catch-all addresses in a small batch. Track bounces
3. Campaign 3: If bounces stayed low, expand the new/unknown batch. If not, remove non-engagers
4. Campaign 4: By now you have engagement data for most catch-alls. Segment by engagement
5. Campaign 5: Suppress any catch-all that hasn't engaged across 4 campaigns. Move the rest to your main list

After this cycle, your catch-all segment is effectively resolved — every address is either engaged (safe to keep) or inactive (removed).

Final Thoughts

Catch-all emails are a grey area, not a red flag. The worst approach is to ignore the distinction entirely and treat them like verified addresses. The second worst is to delete them all and lose real contacts.

The right approach is segmentation, testing, and monitoring. Use EmailVer to identify catch-all addresses in your list, then apply the strategies above to maximize deliverability while preserving every real contact.