Catch-All Emails: The Complete Guide
You've verified your email list. Most addresses came back as "safe" or "invalid"—easy decisions. But then there's that other category: catch-all.
What do you do with these?
Catch-all emails are one of the trickiest challenges in email marketing. They're not clearly good or bad. They exist in a gray zone that can either represent hidden opportunities or hidden landmines for your sender reputation.
This guide explains everything you need to know about catch-all emails: what they are, why they exist, the risks they pose, and exactly how to handle them in your email campaigns.
What Is a Catch-All Email?
A catch-all email (also called an accept-all email) is an address on a domain configured to accept all incoming mail—even if the specific mailbox doesn't exist.
Here's how it works:
Normal email server behavior:
You send to: john.smith@company.com
Server checks: Does john.smith exist?
If yes → Email delivered
If no → Email rejected (bounces back)
Catch-all server behavior:
You send to: john.smith@company.com
Server checks: Is this our domain?
If yes → Email accepted (regardless of whether john.smith exists)
The server never rejects emails. It accepts everything sent to the domain, whether the recipient exists or not.
Why Do Businesses Use Catch-All Configurations?
Catch-all email servers aren't malicious—they serve legitimate business purposes.
1. Preventing Lost Messages
Imagine a potential customer trying to reach your sales team. They type saels@company.com instead of sales@company.com. Without a catch-all, that email bounces and you lose the lead.
With a catch-all configuration, that typo gets captured. Someone can review it and forward it to the right person.
2. Capturing All Inquiries
Businesses want to ensure no customer inquiry falls through the cracks. A catch-all inbox collects everything—even emails sent to addresses that were never created.
3. Protecting Against Email Scraping
Here's a less obvious reason: security.
Many B2B companies configure catch-all servers specifically to prevent email harvesters from discovering valid addresses. When every address appears valid, scrapers can't determine which ones are real.
This is why catch-all domains are especially common in:
- Large enterprises
- B2B companies
- Organizations with strict security policies
- Government and institutional domains
4. Flexibility for Small Teams
A small company might not want to create individual addresses for every employee. With catch-all, they can have one inbox that receives mail for any address—john@, support@, info@, anything@.
The Problem for Email Marketers
While catch-all configurations make sense for businesses receiving email, they create serious challenges for businesses sending email.
You Can't Verify the Actual Mailbox
Normal email verification works by asking the mail server: "Does this mailbox exist?"
With catch-all domains, the server always says "Yes"—even for completely fake addresses like kjsdhfkjsdhf@company.com.
This means:
- We can confirm the domain is valid
- We can confirm the domain accepts mail
- We cannot confirm whether the specific mailbox exists
- We cannot confirm whether anyone reads that inbox
The Statistics Are Concerning
Research shows catch-all emails present real risks:
- Emails sent to accept-all addresses are about 27x more likely to bounce than emails to valid addresses
- 15–25% of B2B emails on average lists turn out to be catch-alls
- The median value of catch-all emails in individual lists is 15.25%, with an average of 541 catch-all emails per list
- Up to 30% of a typical B2B contact list may return "catch-all" or "unknown" results
These numbers are too significant to ignore.
What Happens When You Send to Catch-All Addresses?
When you email a catch-all address, three things can happen:
Scenario 1: Successful Delivery ✅
The mailbox actually exists and someone reads your email. Best case outcome.
Scenario 2: Silent Delivery to Nowhere 📭
The email is accepted but goes to a general inbox that nobody checks. Your message sits unread forever, hurting your engagement metrics.
Scenario 3: Delayed Bounce 💥
The server accepts the email initially but bounces it later. This is the worst case—you think delivery succeeded, but your bounce rate climbs and your sender reputation suffers.
Some catch-all domains are configured to accept emails at the front door, then silently reject them afterward. You won't know until the damage is done.
Risks of Sending to Catch-All Emails
Let's be specific about what's at stake.
1. Higher Bounce Rates
Catch-all domains can't tell you if a mailbox is real. Many addresses you send to will bounce—and email service providers (ESPs) notice.
Industry standard: Keep bounce rates under 2%
Risk with catch-all: Studies show 23% of catch-all emails can hard bounce, potentially pushing your overall bounce rate into dangerous territory.
2. Damaged Sender Reputation
ISPs like Gmail, Outlook, and Yahoo track your sending patterns. High bounces + low engagement = poor sender reputation.
Poor sender reputation means:
- More emails landing in spam folders
- Lower deliverability across your entire list
- Potential blacklisting
3. Spam Trap Exposure
Here's something most marketers don't know: Consumer ISPs like Verizon Media Group have started using catch-all domains for spam traps.
Spam traps are honeypot addresses designed to catch spammers. Hitting one can get your domain blacklisted instantly.
Some catch-all domains contain spam traps mixed in with legitimate addresses. You can't tell which is which.
4. Wasted Resources
You're paying for email sends. Sending to addresses that go nowhere—or worse, bounce—is throwing money away.
5. Skewed Metrics
Catch-all addresses drag down your:
- Open rates
- Click-through rates
- Engagement scores
- Campaign ROI calculations
When a significant portion of your list never engages, your metrics don't accurately reflect how real customers respond.
How Valid Email Checker Handles Catch-All Emails
When you verify an email list with Valid Email Checker, catch-all addresses receive special treatment.
What We Do
- Syntax validation — Is the email format correct?
- Domain verification — Does the domain exist?
- MX record check — Are mail servers configured?
- SMTP verification — Does the server accept connections?
- Catch-all detection — Does the server accept everything?
When we detect a catch-all domain, we mark the email as catch_all status with a score of 71 (moderate confidence).
What We Can't Do
No verification tool can definitively confirm whether a specific mailbox exists on a catch-all domain. The server won't tell us.
Some services claim "advanced catch-all verification"—but the fundamental limitation remains. If a server accepts all emails, you can't verify individual addresses through standard SMTP methods.
Why We Score Catch-All at 71
Our scoring reflects the uncertainty:
| Status | Score | Meaning |
|---|---|---|
| Safe | 98 | High confidence—verified deliverable |
| Role | 93 | Valid team email |
| Catch-All | 71 | Moderate confidence—delivery uncertain |
| Disposable | 30 | Low confidence—temporary address |
| Invalid | 3 | Very low confidence—doesn't exist |
A score of 71 means: "This might be fine, but proceed with caution."
How to Handle Catch-All Emails
You have three options. The right choice depends on your risk tolerance, list source, and campaign goals.
Option 1: Exclude All Catch-All Emails (Conservative)
Best for:
- Cold outreach campaigns
- Purchased or scraped lists
- Senders with deliverability concerns
- New domains building reputation
How to do it:
- Download your verification results
- Filter Status = "catch_all"
- Remove these from your sending list
Pros:
- Zero risk from catch-all addresses
- Cleaner engagement metrics
- Protected sender reputation
Cons:
- You'll lose some valid contacts
- May miss real business opportunities
- Up to 15-25% of your B2B list excluded
Option 2: Send to All Catch-All Emails (Aggressive)
Best for:
- Opted-in lists where contacts confirmed their email
- High-value B2B leads worth the risk
- Senders with strong sender reputation
How to do it:
- Keep catch-all emails in your list
- Send normally
- Monitor bounce rates closely
- Remove any that bounce
Pros:
- Maximum reach
- No lost opportunities
Cons:
- Higher bounce rates
- Potential reputation damage
- Wasted sends on inactive mailboxes
Option 3: Test and Segment (Recommended)
Best for:
- Most email marketers
- Mixed lists with various sources
- Anyone who wants data-driven decisions
This is the smart middle ground. Here's the strategy:
Step 1: Separate Catch-All Emails
After verification, export catch-all addresses into their own segment. Don't mix them with verified safe emails.
Step 2: Send a Small Test Batch
Start with 10-20% of your catch-all list. Send them a normal campaign.
Step 3: Monitor Key Metrics
Watch for:
- Bounce rate — Should stay under 3%
- Open rate — Compare to your safe email segment
- Spam complaints — Any increase is a red flag
Step 4: Evaluate and Decide
If metrics are healthy: Gradually send to more catch-all addresses
If bounces spike: Stop sending to catch-all emails from that batch
Step 5: Remove Non-Engagers
After 2-3 sends with no opens or clicks, remove the address. If someone isn't engaging, there's no point continuing.
Best Practices for Catch-All Emails
1. Know Your List Source
How did these emails get on your list?
| Source | Trust Level | Catch-All Risk |
|---|---|---|
| Double opt-in signups | High | Lower risk—they confirmed |
| Single opt-in forms | Medium | Moderate risk |
| Business card scans | Medium | Moderate risk |
| Purchased lists | Low | High risk—avoid catch-alls |
| Scraped emails | Very low | High risk—exclude catch-alls |
If someone actively gave you their email (and confirmed it), catch-all addresses are safer to send to. If you acquired the email through other means, be more cautious.
2. Limit Catch-All Percentage
Best practice: limit accept-all addresses to a small share of your campaigns (e.g., 2–5%)
Don't let catch-all emails dominate your send volume. Keep them as a small percentage of each campaign.
Example:
- Total campaign: 10,000 emails
- Safe emails: 9,500 (95%)
- Catch-all emails: 500 (5%)
3. Use Dedicated Segments
Never mix catch-all emails with your verified safe list. Keep them separate so you can:
- Track performance independently
- Adjust strategy based on results
- Protect your main list if something goes wrong
4. Send Less Frequently
Catch-all segments don't need every email you send. Consider:
- Only major announcements
- Monthly instead of weekly
- High-value content only
5. Clean Aggressively
Set strict engagement rules for catch-all addresses:
- No opens after 2 emails → Remove
- Bounce once → Remove immediately
- Spam complaint → Remove and investigate
6. Re-Verify Periodically
Catch-all configurations can change. A domain that was catch-all six months ago might not be today (and vice versa).
Re-verify your catch-all segment every 30-60 days.
7. Monitor Your Sender Reputation
Use tools to track your sender reputation while testing catch-all emails:
- Google Postmaster Tools (for Gmail)
- Microsoft SNDS (for Outlook/Hotmail)
- Your ESP's deliverability dashboard
If reputation dips, scale back catch-all sends immediately.
Catch-All Emails in B2B vs. B2C
The catch-all challenge is particularly acute in B2B marketing.
B2B: Higher Catch-All Rates
Business email domains are far more likely to use catch-all configurations than consumer email providers.
- Gmail, Yahoo, Outlook → Not catch-all (they reject invalid addresses)
- Corporate domains → Often catch-all (especially larger companies)
If your list is primarily B2B, expect 15-30% of addresses to be catch-all.
B2B: Higher Stakes
B2B deals are typically higher value. Excluding a legitimate contact because they're on a catch-all domain could cost you a significant deal.
This is why the "test and segment" approach works best for B2B:
- Don't throw away potentially valuable contacts
- Don't risk your sender reputation on unverified addresses
- Let data guide your decisions
B2C: Lower Catch-All Rates
Consumer lists using Gmail, Yahoo, Outlook, and other major providers will have very few catch-all addresses. These providers give clear valid/invalid responses.
If you see high catch-all rates in a B2C list, investigate the source—it might indicate data quality issues.
Common Questions About Catch-All Emails
Are catch-all emails valid?
The domain is valid and accepts mail. Whether the specific mailbox exists and is monitored—we can't confirm. They're in a gray zone between valid and unknown.
Should I delete all catch-all emails?
Not necessarily. If contacts opted in and confirmed their address, they're worth keeping. If the source is questionable, excluding them is safer.
Why did someone give me a catch-all email?
They probably didn't know—or care. Many business email systems are configured as catch-all without employees being aware. To them, it's just their work email.
Can I verify catch-all emails more accurately?
Some services claim advanced catch-all verification using AI, engagement history, or sending test emails. Results vary. The fundamental limitation (servers accepting everything) remains.
Valid Email Checker marks them as catch_all so you can make informed decisions, rather than pretending we have certainty we don't have.
What's the difference between catch-all and unknown?
| Status | What It Means |
|---|---|
| Catch-All | Server accepts all emails—we know this for certain |
| Unknown | Server didn't respond or timed out—we couldn't complete verification |
Catch-all is a definitive status. Unknown means verification couldn't complete.
Do catch-all emails hurt my sender reputation?
Only if you get high bounces or low engagement. Sending to well-maintained catch-all inboxes is fine. Sending to abandoned catch-all addresses hurts you.
This is why testing small batches first is important.
Action Plan: What to Do Right Now
If you have catch-all emails in your list, here's your step-by-step plan:
Step 1: Export and Separate
Download your verification results. Filter for catch_all status. Move these to a separate list or segment.
Step 2: Evaluate Your Source
How did these contacts join your list? Opt-in = lower risk. Purchased/scraped = higher risk.
Step 3: Decide Your Approach
| Your Situation | Recommended Approach |
|---|---|
| New sender / building reputation | Exclude catch-alls for now |
| Opted-in list from known source | Test small batch, expand if healthy |
| Mixed list, unknown sources | Test very cautiously or exclude |
| Purchased / scraped list | Exclude all catch-alls |
Step 4: Test Before Full Send
If keeping catch-all emails, start with 10-20%. Monitor bounces, opens, complaints.
Step 5: Set Removal Rules
After 2 sends with no engagement → Remove After 1 bounce → Remove immediately After spam complaint → Remove and review
Step 6: Document and Learn
Track how your catch-all segment performs over time. Build organizational knowledge about what works for your specific audience.
Quick Reference
| Topic | Key Point |
|---|---|
| What is catch-all? | Server accepts all emails, even to non-existent mailboxes |
| Why risky? | Can't verify specific mailbox; may bounce later |
| Score in Valid Email Checker | 71 (moderate confidence) |
| Typical % in B2B lists | 15-25% |
| Bounce risk | Up to 27x higher than verified valid emails |
| Recommended approach | Test small batch first, monitor, expand carefully |
| When to exclude | Purchased lists, new domains, deliverability concerns |
| When to include | Double opt-in contacts, high-value B2B leads |
| Re-verify frequency | Every 30-60 days |
Next Steps
You now understand catch-all emails better than most email marketers. Time to put that knowledge to work.
→ Verify Your Email List — Identify catch-all addresses in your list
→ Understanding Your Results — Interpret all verification statuses
→ Result Types Explained — Deep dive on every status type
→ Bulk Verification Guide — Upload and verify your list