Search "best email verification service" and you get a wall of lists that all say roughly the same thing. This one is honest about one thing up front: it lives on the Prime Verifier blog, so yes, we put ourselves first. Everything else is built from facts you can check: each vendor's own pricing page, read on 5 October 2026 and linked from our price comparison. Where another service is the better fit, we say so.

An email verifier has one job: tell you whether an address will accept mail before you send to it. What you can compare before signing up is price, what each service charges you for, and what else comes in the box. How well each one handles your particular list, only a test on your own data will tell you.

How we compared them

Price at volume, pay-as-you-go in USD, from each vendor's own pricing page, not the headline "from" price.
What you are charged for. Some services charge for catch-all or unknown results, some refund them, some never charge. On a B2B list this changes the real bill.
Credit expiry, which matters if you verify in bursts.
Free to start, so you can test your own list before paying.
What else is in the box: security certifications, deliverability tools, prospecting.

We do not rank by accuracy. None of the services here, us included, publishes an independent benchmark you can repeat, and accuracy depends heavily on the domains in your list. The fair test is your own, described at the end.

Quick comparison

Service	Best for	100,000 credits	Catch-all results	Credits expire	Free to start
Prime Verifier	Lowest price up to 100k, catch-all free	$120	Free	Never	100 credits
ZeroBounce	A full deliverability suite	$649	Not on its free list	Never with its ONE subscription; otherwise "rules may apply"	100 a month
NeverBounce	CRM sync in the ZoomInfo ecosystem	$400	Not stated	12 months	Free test credits
MillionVerifier	Lowest price at very high volume	$149	Refunded when it cannot verify with certainty	Never	100 credits
Kickbox	SOC 2, very small packs	$500	Not on its refund list	Not stated	100 verifications
Clearout	Verification plus prospecting	$400	Charged	Never (discounted credits may)	100 credits
Verifalia	Security controls, quality levels	$389	Not stated	Credit packs never	25 a day
Bouncer	EU hosting, deliverability kit	$400	Not on its free list	Never	100 credits

Pay-as-you-go prices from each vendor's pricing page on 5 October 2026, before promotions. "Not stated" means the vendor's pricing page does not say. See all eight at six volumes, from 5,000 to 1,000,000 credits.

1. Prime Verifier, best for low prices with catch-all results free

We built Prime Verifier because the verifiers we used kept charging for answers that were not answers. Every check includes a live mailbox test from our own servers, which run on dedicated IPs with correct reverse DNS. When a server accepts an address, we also ask it about a made-up address: if that is accepted too, the domain accepts everything, and the result is catch_all, clearly labelled and free. Unknown and error results are free too, so you pay only for definite answers: valid, invalid or disposable. Microsoft 365 and Outlook addresses go through the same standard check, and the same rules apply over the API, bulk upload (up to 500,000 addresses per file) and 13 native integrations.

On price, we are the cheapest here up to 100,000 credits: $15 for 5,000 and $120 for 100,000, with credits that never expire and 100 free to start, no card. The honest caveats: from 500,000 credits up, MillionVerifier costs less; we have no SOC 2 report yet; and we are the newest name on this list. Try a single address on the free email verifier, or see the full price list.

2. ZeroBounce, best if you want a whole platform

ZeroBounce is the feature-rich option: AI scoring, inbox placement tests, blacklist and DMARC monitoring, warmup and an email finder, with a long track record and a large integration catalogue. It publishes an accuracy figure, which we do not yet. The cost is price: $649 for 100,000 credits and $3,199 for a million on its pricing page. Unknown results and removed duplicates are free. Credits never expire with a ZeroBounce ONE subscription; without one, its pricing page says expiration rules may apply.

Pick it if you want verification, inbox testing, monitoring and warmup from one vendor and price matters less. Compare: Prime Verifier vs ZeroBounce.

3. MillionVerifier, best for very large lists on a budget

MillionVerifier is the price leader at high volume: $299 for 500,000 credits and $449 for a million, with packs up to 50 million and 40+ integrations. Its "risky email refund" gives credits back for any email it cannot verify with certainty, and credits never expire. Its smallest pack is 10,000 credits for $39.

Pick it if you verify hundreds of thousands to millions of addresses at a time and want the lowest price per email. Under 100,000 credits, we cost less. Compare: Prime Verifier vs MillionVerifier.

4. NeverBounce, best if you live in a CRM

NeverBounce is part of ZoomInfo, with a large set of integrations, automatic CRM sync on its Growth plan, and extras such as AI lead scoring on paid plans. Pay-as-you-go is $400 for 100,000 credits and $2,500 for a million, and those credits expire 12 months after purchase. Its pricing page does not say which results are free.

Pick it if you are already in the ZoomInfo ecosystem or want a subscription that syncs your CRM automatically. Compare: Prime Verifier vs NeverBounce.

5. Kickbox, best for SOC 2 and small top-ups

Kickbox's pricing page states SOC 2 certification and sells packs from 500 verifications for $5, which suits teams that only check a few hundred addresses at a time. It refunds the credit for results it cannot make definitive. At volume it is among the pricier options here: $500 for 100,000 and $2,999 for a million. Its pricing page does not say whether credits expire.

Pick it if you need a SOC 2 certified vendor for procurement, or only verify a few hundred addresses at a time. Compare: Prime Verifier vs Kickbox.

6. Clearout, best if you also prospect

Clearout has grown into a wider toolkit: an email finder, form protection, prospecting, a LinkedIn extension and phone validation, and its site states ISO 27001 and SOC 2 Type II certification. Pay-as-you-go is $400 for 100,000 credits and $1,400 for a million. Unknown results and duplicates within an upload are free; its pricing guide says catch-all results use a credit. Purchased credits never expire, and subscriptions roll unused credits over.

Pick it if you want verification, prospecting and enrichment from one vendor, or need ISO 27001 and SOC 2 paperwork. Compare: Prime Verifier vs Clearout.

7. Verifalia, best for fine-grained security controls

Verifalia offers controls we do not, such as configurable data retention and client-certificate (X.509) login, plus three quality levels (Standard, High and Extreme, where the deeper levels use more credits per address) and prices in 21 currencies. Credit packs never expire: $389 for 100,000 and $1,490 for a million. Its free plan gives 25 verifications a day.

Pick it if you need data-retention settings or certificate login, or want to pay in a local currency. Compare: Prime Verifier vs Verifalia.

8. Bouncer, best for EU hosting

Bouncer is hosted in the EU and adds a deliverability kit (inbox placement, blocklist, SPF, DKIM and DMARC tests) and a sign-up form widget. Credits never expire, and duplicates and unknown results are free. It is not the cheapest per email, though: $400 for 100,000 and $2,000 for a million on its pricing page. Its minimum purchase is 1,000 credits for $8.

Pick it if you need EU hosting, or want inbox placement testing from the same vendor. Compare: Prime Verifier vs Bouncer.

Catch-all domains: what a verifier can and cannot tell you

A catch-all domain is set up to accept mail for any address, including ones that do not exist. No mailbox check can confirm an individual address on such a domain: the server says yes to everything. Scores and probabilities, which some services offer, are estimates built from other signals. What a verifier can do is detect the catch-all and tell you plainly, and the billing question is whether you pay for that answer.

If the server rejects the made-up address, it really checks its mailboxes, so its yes to yours means the mailbox exists and the result is valid. If it accepts the made-up one too, the result is catch_all: risky, clearly labelled, and free. On a B2B list, where company domains are often set up this way, treat those addresses as their own segment, for example by mailing them in small, careful batches. More in catch-all emails explained and on catch-all email verification.

How to actually choose

Answer three questions. What is your real volume? Up to 100,000 credits at a time, Prime Verifier is the cheapest here; from 500,000 up, MillionVerifier is. What does your list look like? On a B2B list with many catch-all domains, check what each service charges for those results. And what else do you need: a SOC 2 or ISO report (Kickbox, Clearout), EU hosting (Bouncer), a deliverability suite (ZeroBounce, Bouncer) or prospecting (Clearout)?

Then test. Run the same few hundred addresses through two services, ideally addresses whose fate you already know from past sends, and compare both the results and the bill. Every service here lets you start free. Our explainer on the SMTP check shows what happens during each verification.

Frequently asked questions

What is the most accurate email verification service?

No honest answer fits every list. Accuracy depends on the domains you have, and none of the services here, us included, publishes an independent benchmark you can repeat. Test two or three on a sample of your own list, ideally addresses whose outcome you already know.

Which email verifier is cheapest?

From each vendor's pay-as-you-go prices on 5 October 2026: up to 100,000 credits, Prime Verifier ($15 for 5,000, $120 for 100,000). From 500,000 credits up, MillionVerifier ($299 for 500,000, $449 for 1,000,000), with Prime Verifier next ($400 and $650). Also compare what each one charges for: catch-all results are free with us, refunded at MillionVerifier, and charged at Clearout, per its pricing guide.

Can I verify emails for free?

Yes, every service here has a free way to start: 100 credits with Prime Verifier, MillionVerifier, Clearout and Bouncer; 100 verifications with Kickbox; 100 a month on ZeroBounce's free plan; 25 a day with Verifalia; and free test credits with NeverBounce. You can also check single addresses on our free email verifier with no account.

Try it on your own list. Run a few addresses through the free verifier, then create a free account for 100 verifications with no card.

Best Email Verification Services in 2026: An Honest Comparison