Email verifiers that report coverage
An accuracy claim means little until you know how much of the list it covers. Eight verifiers ranked on whether they show the share of a list they checked.
How this was compared
Disclosure: ZapBounce is our product. Figures were read from each vendor's own pages in September 2026, and the criteria below were applied to every entry, ours included.
The short version
- Coverage shown per job: whether the results count the rows that reached a definite verdict apart from the rows that did not.
- Separate results for catch-all and unknown, so neither is folded into valid or invalid.
- Accuracy claims with a stated denominator, or a published method behind them, as each vendor words it on its own site.
- Billing for rows that reached no verdict, read from each vendor's own pages in September 2026.
- Disclosure: ZapBounce is our product, and the same criteria were applied to it.
At a glance
| 10,000 addresses | Credit expiry | Bills unknowns | |
|---|---|---|---|
| ZapBounce | $25 | Credits never expire | No |
| Hunter | Plans from $49 to $299 a month | Credits expire after 12 months | No |
| Proofy | $18 | Credits never expire, and survive cancellation | No |
| Kickbox | $70 | Credits expire one year from purchase | No |
| Bouncer | $60 | Credits never expire | No |
| Emailable | $0.0076 an address at the 5,000 entry, 15% off on a subscription | Credits never expire | No |
| Mailfloss | $40 prepaid, or $29 a month on Lite | Prepaid credits never expire | Not stated |
| Verifalia | $49.90 at Standard quality | Purchased credits never expire; daily free credits expire each day | Not stated |
Vendor figures read from their own pricing pages in September 2026. Confirm before purchase, because prices move.
The ranking
Best first, with the situation each one fits.
ZapBounce
Disclosure: ZapBounce is our product. Every batch summary counts valid, invalid, catch_all and unknown rows, plus duplicates and a billed total. The share of your list with a definite verdict sits right beside the verdicts, and each row carries the reason and SMTP code behind it.
- Best for:
- Buyers who want to see how much of a list was really checked before trusting the result, at $5 for 1,000 with unknowns never billed. How we measure accuracy sets out the two numbers, and how it works shows the check.
Hunter
Hunter published a benchmark of 15 verifiers on 3,000 real business addresses, itself included, with the method disclosed (dated 3 November 2025).
- Best for:
- Teams who want a vendor's own test method to read before buying.
- Less suited to:
- Seasonal cleans, since credits expire after 12 months (read 24 September 2026).
Proofy
Proofy words its accuracy as up to 99% on conclusive results, which names the denominator, and it never charges for unknowns or duplicates.
- Best for:
- Buyers who read the small print on an accuracy claim.
- Less suited to:
- Testing for free, since new users get a $5 trial rather than free credits.
Kickbox
Kickbox charges only for definitive results and publishes no accuracy figure. Its Sendex score rates the quality of each address.
- Best for:
- Teams who want a quality score on top of the result.
- Less suited to:
- Credits bought ahead of need, since they expire one year from purchase (read 24 September 2026).
Bouncer
Bouncer publishes no accuracy percentage and never charges for duplicates or unknowns.
- Best for:
- Lists where risky domains need flagging with a toxicity check.
- Less suited to:
- Large lists on a tight budget, where its 100,000 tier costs $400.
Emailable
Emailable publishes no accuracy percentage and refunds duplicates and unknowns.
- Best for:
- Lists over 5,000 addresses cleaned in one pass.
- Less suited to:
- Small lists, since purchases start at 5,000 credits.
Mailfloss
Mailfloss publishes no accuracy figure and explains why in its FAQ. It runs hygiene inside your email platform on a schedule.
- Best for:
- Senders who want cleaning to run without uploading a file.
- Less suited to:
- Large one-off cleans on a tight budget, where 100,000 prepaid checks cost $300.
Verifalia
Verifalia reports why each address failed and lets you buy a deeper check at 2 or 4 credits an address.
- Best for:
- Developers who want the failure reason on every row.
- Less suited to:
- Fixed budgets on hard lists, since its High and Extreme levels cost 2 and 4 credits an address.
Why ZapBounce ranks first
How to choose
- Ask for the denominator: Proofy words its claim as up to 99% on conclusive results, which tells you the base. ZapBounce shows the base on every batch, as the count of rows that reached valid or invalid, with catch_all and unknown counted apart.
- Look for a method: Hunter published its 15-vendor test with the method disclosed (3 November 2025). ZapBounce publishes its measuring method on the accuracy page.
- Check what the gaps cost: Kickbox, Bouncer, Emailable and Proofy don't bill unknowns, and neither does ZapBounce, so a low-coverage run costs less, not more.
- Count catch-alls apart: ZapBounce returns catch_all as its own result after one probe, so a list heavy with company domains shows up as catch-all, never as extra valid rows.
Questions people ask
What is coverage in email verification?
Coverage is the share of a list that got a definite verdict. Rows that come back unknown, and catch-all rows that no SMTP check can confirm, sit outside it. A claim of 99% made on 70% coverage leaves almost a third of the list unchecked.
Why is one accuracy figure not enough?
Most vendors work out their figure after the unknown and catch-all rows leave the pool. That number says nothing about how much of your list was checked, so ask for the coverage count beside it.
How do I work out coverage from a verification result?
Add the valid and invalid rows and divide by the total rows checked. Catch-all rows are counted apart, because the server accepted a random address too. ZapBounce's batch summary gives you each count.
Does ZapBounce charge for rows it could not verify?
No. A result of unknown is never billed, and duplicates are removed before billing. Valid, invalid and catch_all results each cost one credit.
Run the same sample through two of them
100 free checks a month, no card. Compare how many addresses each one declined to judge, which matters more than either accuracy claim.