Email verification tools compared: ZeroBounce, NeverBounce, MillionVerifier and Bouncer

The short answer

For most founders sending cold email, MillionVerifier is the cheapest serious option (about $39 for 10,000 checks, credits that never expire), and Bouncer is the balanced pick at $60 for 10,000 with a resolver for some catch-all addresses. ZeroBounce costs the most per check but returns the most detail, including a score for catch-all addresses and spam trap flags.

NeverBounce suits teams that want a list in HubSpot or a newsletter tool re-cleaned automatically every day. Whichever you pick, verify every list before every campaign: practitioners hold bounces at 2 percent or less, and lists decay every month.

Why verify before every campaign

A bounce hurts the domain you send from, not the list you bought. Google's sender guidelines give no bounce percentage, but they tell mailbox operators to unsubscribe recipients who have multiple bounced messages, and they hold bulk senders to a spam rate below 0.1 percent, never reaching 0.3 percent. Yahoo asks senders to remove invalid recipients promptly.

Practitioners set the working line. Smartlead and lemlist both advise keeping bounces at 2 percent or less, and lemlist puts the average across platforms at 5.1 percent. The gap between those two numbers is mostly unverified lists.

Lists also go stale on their own. HubSpot estimates that email databases degrade by about 22.5 percent a year, citing MarketingSherpa research of 2.1 percent a month. ZeroBounce's own data, across 11 billion addresses it processed, shows at least 23 percent decay in 2025 and 28 percent in 2024. A list that was clean last quarter is not clean today.

The four tools at a glance

Email verification tools: price, credits, catch-alls and data handling

	ZeroBounce	NeverBounce	MillionVerifier	Bouncer
10,000 checks, pay as you go	About $129 ($0.0129 each)	About $80 ($8 per 1,000)	About $39	$60
100,000 checks	About $649	Not on its pricing page	$149	$400
Monthly plan	ZeroBounce ONE: $99 a month for 10,000, $79 billed annually	Growth: $49 a month for up to 10,000, with daily auto-sync	None: one-off payments	Subscription offered; current price not confirmed
Do credits expire?	Two years after your last purchase, on accounts opened after June 2026	12 months after purchase	Never	Never
Free checks	100 a month with a business domain	10 on sign-up	100	100
Catch-all addresses	AI score from 0 to 10, one extra credit each	Flagged as catch-all	Catch-All Verifier (beta); unresolved checks refunded	Marked risky; resolves some on Google and Microsoft
Unknown results charged?	No	Not stated	No, credits returned	No
Refund promise	99.6% accuracy guarantee, with a refund formula	Refund if bounces exceed 3% (conditions apply)	Refund if hard bounces exceed 4%	Not stated
Security and privacy	SOC 2 Type 2; GDPR	GDPR addendum; no SOC 2 report found	GDPR; servers in Hungary and Sweden	SOC 2 Type 1, Type 2 in progress; EU data
Uploaded files deleted	Within 30 days	After 90 days	Within 30 days	On a retention period you set

What a result tells you

Every verifier checks the address's syntax, the domain's mail servers and, where it can, whether the mailbox exists, then returns a status. The four agree on the basics (valid, invalid, catch-all, unknown, disposable) and differ on the extras: ZeroBounce also flags spam traps, abuse and toxic addresses; Bouncer runs a separate toxicity check; MillionVerifier adds a good, risky or bad quality field.

Catch-all addresses: the hard part

A catch-all domain accepts mail for any address, so the usual mailbox check cannot tell a real person from a typo. B2B lists are full of them, because many company mail servers are set up this way. This is where the tools differ most.

• ZeroBounce scores catch-all addresses from 0 to 10 with its AI scoring, for one extra credit each (so two credits to validate and score). It says plainly that a score does not confirm the address is valid.
• MillionVerifier runs a separate Catch-All Verifier (in beta) for one credit, takes about 10 to 30 seconds per address, and returns your credit when it cannot resolve one.
• Bouncer marks accept-all addresses as risky, and says it can resolve some catch-alls hosted on Google and Microsoft.
• NeverBounce flags them as catch-all and leaves the decision to you.

Accuracy: what the tests show

Every vendor claims 99 percent or better: ZeroBounce 99.6, NeverBounce up to 99.9, MillionVerifier 99, Bouncer 99.5. The published tests disagree with each other, and none is independent. ZeroBounce ran its own benchmark in July 2026 on 9,901 hard cases and came first. Hunter, a competing vendor, tested 15 tools on about 3,000 addresses with unknown results counted as wrong, and came first. La Growth Machine ran a third test without explaining its method.

The ranking flips from test to test, mostly because each one treats unknown and catch-all results differently. Read accuracy claims as a reason to test a sample of your own list, not as a reason to pick a tool.

Integrations for cold email

Where each verifier connects, from its own documentation

	ZeroBounce	NeverBounce	MillionVerifier	Bouncer
HubSpot	Native	Native, re-cleaned every 24 hours with Sync	Native	Native, with AutoClean
Clay	Native action	With your own account	With your own account, on Clay's Growth plan and up	Not confirmed
Zapier	Yes	Yes	Yes	Not confirmed
Make	Through a third party	Not confirmed	Not found	Yes
Smartlead	Not confirmed	Not confirmed	Yes	Not confirmed
Instantly	Not confirmed	Not confirmed	Through an n8n workflow	Not confirmed

The four tools

MillionVerifier

Lowest cost

Best for: founders and agencies verifying lists in bulk who want the lowest price and credits that never run out.

Strengths

• About $39 for 10,000 checks, $149 for 100,000
• Credits never expire; no subscription needed
• Unknown and unresolved catch-all checks refunded
• Native Smartlead and HubSpot connections

Watch-outs

• No role or spam trap flags in its result codes
• No independent accuracy test found
• Third-party guides quote slightly different prices

Skip it if: you need spam trap and toxic address detection; ZeroBounce returns those.

Pricing: About $39 for 10,000, $89 for 50,000, $149 for 100,000; one-off payments.

Bouncer

Balanced

Best for: teams that want a mid-priced verifier with a toxicity check and EU data handling.

Strengths

• $60 for 10,000, $400 for 100,000; credits never expire
• No charge for duplicates or unknown results
• A toxicity check that flags breached addresses and possible spam traps
• Resolves some catch-alls on Google and Microsoft

Watch-outs

• SOC 2 Type 1 only so far, with Type 2 in progress
• Fewer documented outbound integrations
• Current subscription price not published clearly

Skip it if: your list mostly sits in Clay or a sequencer it does not connect to.

Pricing: $8 for 1,000, $60 for 10,000, $400 for 100,000, pay as you go.

ZeroBounce

Most detail

Best for: senders who want the fullest result on every address, including catch-all scores and spam trap flags.

Strengths

• The most detailed statuses: spam trap, abuse, toxic and role
• AI scoring for catch-all addresses
• SOC 2 Type 2 and GDPR
• Native HubSpot, Zapier and a Clay action

Watch-outs

• The highest price per check of the four
• Scoring a catch-all costs a second credit
• Credits now expire two years after your last purchase on new accounts

Skip it if: price per check is your main constraint; MillionVerifier costs about a third as much.

Pricing: About $129 for 10,000 and $649 for 100,000 pay as you go; ZeroBounce ONE at $99 a month for 10,000.

NeverBounce

Auto-clean

Best for: teams that want a HubSpot list or newsletter audience re-cleaned automatically every day.

Strengths

• Sync re-verifies connected lists every 24 hours
• Fast: 10,000 addresses in about 3 minutes
• A refund if bounces exceed 3 percent, under conditions

Watch-outs

• Pay-as-you-go credits expire after 12 months
• Only five result codes, with no role or spam trap flag
• Scored lowest in ZeroBounce's test, with half its results unknown

Skip it if: you verify one-off cold lists and want credits that keep.

Pricing: $8 per 1,000 pay as you go; Growth at $49 a month for up to 10,000 with auto-sync.

Alternatives worth a look

Other verifiers founders compare

Tool	10,000 checks	Credits expire?	Free to start	Worth knowing
DeBounce	About $25	Never	Not confirmed	The lowest price we found
Emailable	$60, or $51 on a subscription	Never	250 free checks	Unknowns and duplicates refunded
Clearout	About $65	Never	100 free credits	Not stated
Kickbox	About $80	Not confirmed	Not confirmed	A 0 to 1 quality score (Sendex)
Hunter	Plans by credits	Monthly credits	50 credits a month, about 100 checks	Built into an email finder

A verification routine that holds

Verify at the last moment, not when you buy the data: B2B data loses about 2 percent a month by HubSpot's estimate, so a list verified at purchase and sent three months later has already slipped. Keep catch-all addresses in their own small batches so a bad one cannot drag the whole campaign down.

For the sending tools a verified list feeds, see Instantly vs Smartlead (opens in a new tab); for where verification sits in the whole stack, see the GTM tech stack for early-stage founders (opens in a new tab).

Questions

What is the best email verification tool?

It depends on volume and detail. MillionVerifier is the cheapest serious option at about $39 for 10,000 checks with credits that never expire. Bouncer is the balanced pick at $60. ZeroBounce costs the most but returns the most detail, including catch-all scores and spam trap flags.

How much does it cost to verify 10,000 emails?

From about $25 (DeBounce) to about $129 (ZeroBounce) as a one-off pack, as of October 2026. MillionVerifier is about $39, Bouncer and Emailable $60, NeverBounce about $80 at $8 per 1,000.

What is a catch-all email address?

An address on a domain whose mail server accepts mail for any address, so a verifier cannot confirm the mailbox exists. ZeroBounce scores them, MillionVerifier runs a separate check, and Bouncer resolves some on Google and Microsoft. Send them in small batches, if at all.

How accurate are email verifiers?

Every vendor claims 99 percent or more, but the published tests disagree and each was run by a vendor. In ZeroBounce's test ZeroBounce came first; in Hunter's, Hunter did. Test a sample of your own list before you commit.

What bounce rate is safe for cold email?

Practitioners such as Smartlead and lemlist advise 2 percent or less. Google publishes no bounce threshold, but its guidelines ask senders to stop mailing addresses that bounce repeatedly, and hold the spam rate below 0.3 percent.

Do I need to verify a list my data provider already verified?

Yes, if time has passed. HubSpot estimates B2B data decays about 2 percent a month, so verify right before each campaign, not only when the data was bought.

Sources

1. Email validation pricing (opens in a new tab), ZeroBounce, checked October 18, 2026
2. Status codes explained (opens in a new tab), ZeroBounce, checked October 18, 2026
3. Email verification accuracy benchmark 2026 (opens in a new tab), ZeroBounce, checked October 18, 2026
4. The email list decay report for 2026 (opens in a new tab), ZeroBounce, checked October 18, 2026
5. Cybersecurity and data privacy compliance (opens in a new tab), ZeroBounce, checked October 18, 2026
6. Email verification pricing (opens in a new tab), NeverBounce, checked October 18, 2026
7. Result codes (opens in a new tab), NeverBounce, checked October 18, 2026
8. Our guarantee (opens in a new tab), NeverBounce, checked October 18, 2026
9. Bulk email verifier (opens in a new tab), MillionVerifier, checked October 18, 2026
10. Email verification results (opens in a new tab), MillionVerifier, checked October 18, 2026
11. Accuracy rate (opens in a new tab), MillionVerifier, checked October 18, 2026
12. Email verification pricing (opens in a new tab), Bouncer, checked October 18, 2026
13. Terminology (opens in a new tab), Bouncer, checked October 18, 2026
14. SOC 2 for email verification (opens in a new tab), Bouncer, checked October 18, 2026
15. 15 best email verification tools in 2026 (opens in a new tab), Hunter, checked October 18, 2026
16. Best email verification services 2026 (opens in a new tab), La Growth Machine, checked October 18, 2026
17. Email sender guidelines FAQ (opens in a new tab), Google, checked October 18, 2026
18. Email sender guidelines (opens in a new tab), Google, checked October 18, 2026
19. Sender best practices (opens in a new tab), Yahoo, checked October 18, 2026
20. How to reduce email bounce rates for cold outreach (opens in a new tab), Smartlead, checked October 18, 2026
21. Cold email response rate (opens in a new tab), lemlist, checked October 18, 2026
22. Database decay simulation (opens in a new tab), HubSpot, checked October 18, 2026
23. Emailable FAQ (opens in a new tab), Emailable, checked October 18, 2026
24. Pricing (opens in a new tab), DeBounce, checked October 18, 2026
25. Frequently asked questions about Canada's anti-spam legislation (opens in a new tab), CRTC, checked October 18, 2026
26. Automated email list cleaning (Sync) (opens in a new tab), NeverBounce, checked October 18, 2026
27. NeverBounce home page (opens in a new tab), NeverBounce, checked October 18, 2026
28. MillionVerifier home page (opens in a new tab), MillionVerifier, checked October 18, 2026
29. All integrations (opens in a new tab), MillionVerifier, checked October 18, 2026
30. Catch-all email verification (opens in a new tab), Bouncer, checked October 18, 2026
31. Validate email with ZeroBounce (opens in a new tab), Clay, checked October 18, 2026
32. Clearout vs ZeroBounce (opens in a new tab), Clearout, checked October 18, 2026
33. Kickbox pricing (opens in a new tab), Toolradar, checked October 18, 2026
34. Emailable vs ZeroBounce (opens in a new tab), Emailable, checked October 18, 2026

How these comparisons are made: from each vendor's own documentation and pricing pages, independent reviews and the policies of the platforms involved, each linked and dated. Prices change often; check the vendor's page before you buy.