If you are reading this, you are probably already using MillionVerifier and something has started to grate — a batch of "unknown" results you cannot act on, a support ticket that went quiet, or the fact that cleaning a 3,000-contact list means buying 10,000 credits.
Here is the short version. MillionVerifier is a good product. It is one of the cheapest bulk verifiers on the market at very large volumes, credits never expire, and there is no subscription to cancel. If you are verifying a million addresses at a time, it is hard to beat on price.
Below that, the picture changes. At the volumes most marketing and sales teams actually work with — 2,500 to 100,000 addresses — CampaignKit is cheaper, starts at a fraction of the minimum spend, and returns a result you can do something with on the addresses MillionVerifier leaves ambiguous.
This comparison covers both, including a section on when you should stay exactly where you are.
Credit where it is due, because it explains why the product has the following it does.
The pricing model is honest. You buy credits, they never expire, and there is no monthly subscription quietly billing you between campaigns. For teams that clean a list twice a year, that model beats a subscription every time.
It is genuinely cheap at scale. At a million verifications the per-address cost drops well under a tenth of a cent. Very few providers compete there.
It is fast, and the integration catalog is broad. Bulk uploads process quickly, and MillionVerifier offers 40+ one-click integrations — Mailchimp, HubSpot, ActiveCampaign, SendGrid and more. That catalog is larger than ours, and if your stack depends on one of those native connections, it matters.
EverClean handles recurring hygiene. Their subscription product re-verifies your list automatically on an ongoing basis, which is a real convenience if you would rather not wire that up yourself.
There is a free tier to test with. 100 credits, no credit card.
So why do people go looking for an alternative?
This is the complaint that comes up most often in user reviews on G2 and Capterra, and it is worth understanding why it matters rather than just noting it.
A catch-all domain accepts mail sent to any address, real or not. Its server answers 250 OK to everything, so SMTP-based verification cannot tell a real mailbox from a fabricated one. Every verification provider hits this wall — it is a property of the receiving server, not a bug in the tool. What separates providers is what they do next.
MillionVerifier's approach leaves a large share of those addresses in an "unknown" or "risky" bucket. Reviewers have asked repeatedly for a clearer explanation of what actually qualifies as "unknown," because as delivered, the result is not actionable: you are handed a pile of addresses and no basis for deciding which to send to.
Benchmarks published by competing vendors put hard numbers on this — one, from Allegrow, reports 67.7% of enterprise catch-all records left unresolved with a 12.8% false-positive rate. Treat those figures with appropriate skepticism, since the companies publishing them sell competing products. The pattern they describe, though, matches what MillionVerifier's own users say.
If catch-alls are a large part of your list — and in B2B they usually are — this is the thing most likely to push you elsewhere. We have written a full guide on what catch-all emails are and how to handle them if you want to go deeper.
MillionVerifier advertises 99%+ accuracy. An independent benchmark run by LeadMagic across 10,000 addresses measured 95.8%.
A 1.8% false-positive rate sounds small until you scale it. On a 100,000-address send, that is roughly 1,800 addresses marked "Good" that still bounce — a 1.8% bounce rate, landing right at the threshold where mailbox providers start throttling you. The entire point of paying for verification is to stay under that line.
MillionVerifier's site promises quick replies. User reviews tell a more mixed story, with reports of waits of up to 72 hours on API and billing issues. Billing disputes — unexpected charges, credits slow to return after a refund request — surface repeatedly in G2 and Trustpilot reviews. When a validation job is blocking a campaign launch, a three-day reply is not a minor inconvenience.
MillionVerifier's entry package is 10,000 verifications for $39. If your list is 3,000 contacts, you are buying 10,000 credits to clean it. They never expire, so nothing is technically wasted — but it is $39 of upfront commitment to try a tool on a small list.
You get Good, Risky, or Bad. There is no per-address quality score and no reason code explaining why a given address landed where it did. For a simple bulk clean that is enough. For deciding which half of your risky segment is worth a re-engagement campaign, it is not.
First, price. Both services use prepaid credits that never expire, which makes the comparison unusually clean.
| Volume | CampaignKit | MillionVerifier |
|---|---|---|
| 2,500 | $6 | not available |
| 5,000 | $12 | not available |
| 10,000 | $15 | $39 |
| 25,000 | $38 | — |
| 50,000 | $75 | $89 |
| 100,000 | $120 | ~$149 |
| 1,000,000 | custom quote | ~$449 |
Prices as of September 2026. MillionVerifier's published tiers vary between sources above the 50,000 mark — check their pricing page for current figures.
The pattern is consistent: CampaignKit is cheaper at every volume a small or mid-sized team actually buys, and MillionVerifier wins decisively once you are past roughly half a million addresses. At 10,000 emails the gap is 62%. On a 3,000-contact list it is $12 against $39.
Now features.
| CampaignKit | MillionVerifier | |
|---|---|---|
| Entry price | $6 (2,500 credits) | $39 (10,000 credits) |
| Free credits | 200 | 100 |
| Credits expire | Never | Never |
| Result format | 0–10 quality score + status | Good / Risky / Bad |
| Typo suggestions | Yes | No |
| Email finder | Yes, same credit pool | No |
| Charged for failed syntax checks | No | — |
| MCP endpoint for AI clients | Yes | No |
| Automated recurring cleaning | Via API + webhooks | Yes, EverClean |
| One-click integrations | Zapier, n8n, HubSpot, Mailchimp, Mailjet | 40+ |
| Hosting | Germany, EU only | EU (Hungary) |
| Guarantee | 30-day money back | Refund on unverifiable addresses |
Two rows there go to MillionVerifier, and they are not trivial ones. More on that below.
This is most teams. The price table above is the whole argument: a 10,000-address clean costs $15 instead of $39, and you can start at $6 rather than $39. Credits never expire on either service, so there is no "use it or lose it" pressure on either side — you are simply paying less for the same job.
Every address CampaignKit returns carries a 0–10 quality score alongside its status. A catch-all address that sits on a domain with clean MX configuration, no blocklist history and a plausible mailbox pattern scores very differently from one that does not — and you can set your own threshold rather than accepting someone else's binary verdict.
That turns an unusable "unknown" pile into a ranked list. Send to the top of it, suppress the bottom, and decide for yourself where the line sits based on how much bounce risk your sender reputation can absorb.
CampaignKit's Email Finder discovers professional addresses from a name and a company domain, drawing on the same credits as validation — 5 credits per successful match, and nothing charged when no address is found. MillionVerifier does not offer email finding at all, so if you need both, that is two vendors and two invoices.
Validation credits work the same way: a syntax check that fails costs you nothing.
The REST API is available on every plan, with webhooks that fire on job completion so you can wire up recurring cleaning inside your own systems. Zapier, n8n, HubSpot, Mailchimp and Mailjet integrations are there for the no-code path.
CampaignKit also exposes a Model Context Protocol endpoint, which lets Claude and other LLM clients validate addresses, launch jobs and pull results directly as tools. If you are building agentic workflows around your CRM or outbound stack, that is a meaningful head start. The developer documentation covers both.
Both companies are EU-based — MillionVerifier operates out of Hungary — so this is not the US-versus-Europe question it would be against a US provider. The difference is in the specifics: CampaignKit runs entirely on servers in Germany operated by Hetzner, with no data leaving the EU, a data processing agreement available to every customer, and our handling of uploaded lists documented on the security page. If your procurement process asks where a list physically sits while it is being processed, that is a short answer to give.
Three cases, and they are real.
You verify at seven-figure volumes. Around a million addresses, MillionVerifier's per-address price is very difficult to beat, and the gap widens above that. We quote custom pricing at those volumes — talk to us — but we are not going to pretend the list price comparison favours us there.
You depend on EverClean. Automated, always-on list hygiene as a managed subscription is a genuinely good product. CampaignKit gets you to the same outcome through the API and webhooks, but that is engineering work, not a checkbox.
You need one of their native integrations that we do not have. 40+ one-click connections is a wider catalog than ours. If your workflow hangs on a native ActiveCampaign or SendGrid connection, switching means building that bridge yourself.
If none of those three describe you, the price and result-quality arguments above apply.
We would rather you make an informed choice than take our word for it. The other serious options:
For a wider survey, see our ranked review of email verification tools.
Do not take the comparison on faith. Run both and look at the output.
Step 4 is the one that decides it. If the scores do not tell you anything MillionVerifier did not, you have lost fifteen minutes and nothing else.
Is CampaignKit cheaper than MillionVerifier? At volumes up to roughly 100,000 addresses, yes — $15 versus $39 at 10,000, $75 versus $89 at 50,000. Above about half a million, MillionVerifier is cheaper.
Do CampaignKit credits expire? No. Credits from any OneTime Pass purchase stay in your account until you use them, with no subscription and no monthly minimum.
How does CampaignKit handle catch-all domains? Catch-all domains are detected and flagged, and every address receives a 0–10 quality score so you can rank ambiguous results and set your own send threshold rather than accepting a binary verdict. No verification service can definitively confirm a mailbox behind a catch-all — anyone claiming otherwise is overselling.
Is CampaignKit GDPR compliant, and where is my data stored? Yes. All processing happens on servers in Germany operated by Hetzner, no data leaves the EU, and a data processing agreement is available to every customer.
Can I import my existing MillionVerifier list? Yes. Export as CSV and upload it directly — no reformatting needed. Excel files work too.
Is there an API and a free trial? The REST API is included on every plan, with webhooks for job completion and an MCP endpoint for AI clients. Every new account gets 200 free validations without a credit card.
The argument in this article is a testable one, and you do not need to spend anything to test it. Sign up for free and you get 200 validations, no credit card required. Run a sample of your list through both services and compare what comes back — particularly on the addresses MillionVerifier could not resolve.
If it works for you, credits start at $6 and never expire, and there is a 30-day money-back guarantee on every purchase. See the pricing page for the full table.
Start with 200 free validations. Upgrade only when you're ready.
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