Best email deliverability tools
Deliverability rests on a clean list, correct DNS records and a sender reputation you watch. Seven tools ranked on what they cover and what they cost.
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
- List quality: verification that removes dead addresses before they bounce, since bounces are the first thing mailbox providers hold against a sender.
- Authentication: tools to check and build SPF, DKIM and DMARC records.
- Reputation and placement: blacklist checks and a test message that shows how a real send is received.
- Cost to start and how credits are billed, 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 |
| ZeroBounce | Subscription only | Credits roll over while the subscription is active | Not stated |
| Kickbox | $70 | Credits expire one year from purchase | No |
| MailerCheck | $0.01 a credit, with no volume tier published | Credits never expire | Not stated |
| Bouncer | $60 | Credits never expire | No |
| Mailfloss | $40 prepaid, or $29 a month on Lite | Prepaid credits never expire | Not stated |
| Allegrow | $8 per 1,000 add-on credits, on a plan from $99 a month (Starter) | Not published | 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. Upload a list or call the API, and each address comes back valid, invalid, catch_all or unknown from our own SMTP check, closed before any message is sent. Free tools on the same site check and generate SPF and DMARC records, look up DKIM and MX, check blacklists and run a send-to-address deliverability test.
- Best for:
- Senders who want the list cleaned and the setup checked in one place, from $5 per 1,000 checks with 100 free a month. See bulk verification, the DMARC checker and how the check works.
ZeroBounce
ZeroBounce sells a broad deliverability suite: inbox placement, blacklist monitoring, DMARC tooling and activity data beside verification.
- Best for:
- Teams that want monitoring and placement tests on one paid account.
- Less suited to:
- A single small clean, given the 2,000-credit entry minimum at $39.
Kickbox
Kickbox is a deliverability consultancy that also sells verification, with a Sendex score on each address and unknowns refunded.
- Best for:
- Senders who want consulting help with a reputation problem.
- Less suited to:
- Credits bought ahead of need, since they expire one year from purchase (read 24 September 2026).
MailerCheck
MailerCheck spends one credit wallet across verification, inbox placement tests and email insights, with a 1,000-credit minimum at $10.
- Best for:
- Teams that want placement tests and list checks paid from one balance.
- Less suited to:
- Volume buyers, since it publishes no volume tier beyond $0.01 a credit.
Bouncer
Bouncer pairs verification with a deliverability kit and a toxicity check, and never charges for duplicates or unknowns.
- Best for:
- Senders who want risky domains flagged in the list.
- Less suited to:
- Large lists on a tight budget, where its 100,000 tier costs $400.
Mailfloss
Mailfloss runs list hygiene inside your email platform on a schedule and repairs mistyped addresses instead of deleting them.
- Best for:
- Senders who want hygiene to run without anyone uploading a file.
- Less suited to:
- Large one-off cleans on a tight budget, where 100,000 prepaid checks cost $300.
Allegrow
Allegrow sells verification as add-on credits at $8 per 1,000 on top of a monthly plan that starts at $99 on Starter, read on allegrow.co on 24 September 2026.
- Best for:
- Outbound teams already on an Allegrow plan.
- Less suited to:
- Buyers who want verification without a monthly plan.
Why ZapBounce ranks first
How to choose
- Start with the list: if your bounce rate is climbing, clean first. ZapBounce charges $25 for 10,000 checks; Kickbox charges $70 for the same volume (read 24 September 2026).
- Suite or separate tools: ZeroBounce sells placement and monitoring on a subscription, and Allegrow on a monthly plan from $99. ZapBounce's DNS, blacklist and test-send tools are free, and you pay only for list checks.
- Automatic or on demand: Mailfloss runs inside your email platform on a schedule. ZapBounce runs on demand by upload or API, so you clean before a big send and check signups as they arrive.
- Minimums: ZeroBounce starts at 2,000 credits and MailerCheck at 1,000. ZapBounce has no minimum purchase, so a small list starts at $5 for 1,000 checks.
Questions people ask
What tools do I need for email deliverability?
Four jobs: a verifier to remove dead addresses, SPF, DKIM and DMARC checks for authentication, a blacklist check for your sending IP and domain, and a test send before big campaigns. ZapBounce covers all four, and only the list checks are paid.
What bounce rate hurts deliverability?
Keep hard bounces under 2% of a send, and treat anything near 5% as a list problem to fix before the next campaign. Track it across sends with the free bounce rate calculator on ZapBounce.
Does email verification improve deliverability?
It removes the addresses that would hard bounce, which is the part of sender reputation you control most directly. It does not change your copy or your DNS records, so pair it with the authentication checks.
How much do deliverability tools cost?
The DNS, blacklist and test-send checks on ZapBounce are free. List verification costs $5 for 1,000 addresses, $25 for 10,000 and $139 for 100,000, with 100 free checks every month.
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.