Best email verifiers for Instantly and Smartlead
Cold email tools warm your inboxes but can't fix a lead list full of dead addresses. Eight verifiers ranked on catch-all handling, billing and price.
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
- Catch-all handling: whether catch-all addresses come back as their own result, since a large share of B2B leads sit on domains that accept every address.
- The route into Instantly and Smartlead: a CSV that keeps your personalisation columns, plus an API or Zapier step for leads added later.
- Billing for unknown and duplicate rows, and whether credits expire between campaigns.
- Published price at 10,000 addresses, 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 |
| Reoon | $11.90 | Instant credits never expire | Not stated |
| MillionVerifier | Not shown in the tiers we could read | Credits never expire, stated twice on their page | 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 |
| Hunter | Plans from $49 to $299 a month | Credits expire after 12 months | No |
| DeBounce | Tiered from 5,000 to 5,000,000 | Credits never expire | Not stated |
| Kickbox | $70 | Credits expire one year from purchase | No |
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. Upload the lead export and every row comes back with one of four results: valid, invalid, catch_all or unknown. Your first-name, company and custom columns stay in place, so the cleaned file imports straight back into a campaign. Our own SMTP check closes the connection before any message is sent, so no prospect ever gets a test email.
Reoon
Reoon runs a five-step deep verification and gives each address a score from 0 to 100.
- Best for:
- Senders who want a numeric score to set their own cut-off.
- Less suited to:
- Budgeting on unknown rows, since its pricing page does not state whether unknowns are billed.
MillionVerifier
MillionVerifier sells pay-as-you-go credits that never expire and refunds any address it could not verify with certainty.
- Best for:
- Agencies buying a very large pack, with 1,000,000 checks at $449 (read 24 September 2026).
- Less suited to:
- Teams who want a monthly plan, since it sells pay-as-you-go only.
Bouncer
Bouncer never charges for duplicates or unknowns, and its toxicity check flags risky domains in a lead list.
- Best for:
- Lead lists pulled from many sources, where risky domains creep in.
- Less suited to:
- Large lists on a tight budget, where its 100,000 tier costs $400.
Emailable
Emailable refunds duplicates and unknowns, and its credits never expire.
- Best for:
- Outbound teams cleaning more than 5,000 leads per batch.
- Less suited to:
- A single small campaign, since purchases start at 5,000 credits.
Hunter
Hunter is an email finder first, with verification at half a credit, and it published a 15-verifier benchmark with its method disclosed.
- Best for:
- Teams who find and verify leads in the same tool.
- Less suited to:
- Seasonal outbound, since credits expire after 12 months (read 24 September 2026).
DeBounce
DeBounce prices checks from $0.00045 each and connects to many email platforms.
- Best for:
- High-volume senders where a low per-check rate compounds.
- Less suited to:
- Catch-all-heavy B2B lists, since catch-all validation costs extra credits per address.
Kickbox
Kickbox refunds unknowns and rates each address with its Sendex score.
- Best for:
- Teams who want a quality score beside each result.
- Less suited to:
- Credits bought ahead of need, since they expire one year from purchase (read 24 September 2026).
Why ZapBounce ranks first
How to choose
- Catch-all rows: DeBounce charges extra credits to validate catch-alls. ZapBounce returns catch_all as one billed result, with no add-on, so you decide how to send to those rows.
- Credits between campaigns: Kickbox and Hunter credits expire after a year (read 24 September 2026). ZapBounce credits never expire.
- Lead volume: Emailable starts at 5,000 credits. ZapBounce starts at $5 for 1,000, so a single client's test list costs little.
- Leads added mid-campaign: ZapBounce checks one address at a time through POST /v1/verify, from your own code or a Zapier step, before the lead reaches a sequence.
Questions people ask
Does Instantly verify emails?
Instantly verifies a list when you run its verification step, and it labels each address valid, invalid, or risky or unknown, according to instantly.ai in September 2026. That last label joins catch-all and unknown rows, which a cold email list needs split before you send.
How do I verify leads before importing them into Instantly or Smartlead?
Export the list as a CSV, upload it to ZapBounce and download the result, which keeps your original columns plus a result per row. Import the valid rows into your main campaign and the catch-all rows into a separate one.
Should I send cold email to catch-all addresses?
Send to them after your valid rows, from a separate campaign with lower daily volume. Many belong to real people at companies whose server accepts every address, so deleting them all loses good leads.
What bounce rate is safe for cold email?
Keep hard bounces under 2% of a send. Above that, mailbox providers start to treat the sending domain as careless, and your warmed inboxes lose the reputation they built.
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.