email verification · list hygiene · api
Your list is lying to you.
We find the emails that will bounce — before you send.
Null-Bounce checks every address at the mailbox level: SMTP handshakes, dead domains, disposable signups, typo repair. Pay per verification, or by the month. 100 free credits to start.
- 99.2%
- accuracy on delivered verdicts
- 2.4s
- average single verification
- 1,000/s
- bulk throughput per job
Try it live:
5 free checks per day · DNS-level result · no signup
Three checks. One verdict.
01
Syntax & domain intelligence
RFC-level parsing, gmail dot/tag canonicalization, typo detection (gmial.com → gmail.com), disposable and role-account flags. Dead domains are killed here — no send required.
02
Mailbox handshake
We connect to the domain's real mail exchangers and ask — without sending mail — whether the specific mailbox exists. Catch-all servers are flagged risky instead of guessed.
03
Honest unknowns
Greylisted or probe-blocking providers (Yahoo, AOL) come back unknown — never a fake valid. Unknowns are refunded on bulk jobs. You always know what you know.
Five verdicts. No hedging.
Every result is one of five states, color-coded everywhere in the product — dashboard, CSV exports, API responses.
Mailbox confirmed via SMTP handshake. Safe to send.
Syntax broken, domain dead, or mailbox rejected. Do not send.
Catch-all, implicit-MX, or typo-suspected. Send with caution.
Server wouldn't answer. Refunded on bulk jobs.
Deliverable, but disposable or role account.
Pricing that scales down as you scale up
Full pricing →1,000 credits
$15
$0.015 / verification
5,000 credits
$60
$0.012 / verification
25,000 credits
$250
$0.010 / verification
Starter
$29/mo
2,500 credits / month
Growth
$99/mo
10,000 credits / month
Business
$399/mo
50,000 credits / month, priority queue
Questions engineers actually ask
Do you send email to verify addresses?
No. Verification uses SMTP RCPT TO handshakes — we ask the mail server if the mailbox exists and disconnect before any message is transferred. No mail is ever delivered to your leads.
What happens with Yahoo, AOL, and Comcast addresses?
Consumer providers aggressively block verification probes to prevent directory harvesting. We return unknown rather than guess — and unknowns are refunded on bulk jobs. Business domains verify at full depth.
What's a catch-all domain and why is it 'risky'?
Some servers accept mail for any address at their domain, then quietly discard it. We probe with a deliberately nonexistent mailbox to detect this — if everything 'exists', no individual address can be confirmed, so we flag risky instead of lying.
Do credits expire?
Credit packs never expire. Monthly plan credits reset each billing cycle — they don't roll over, which is why the per-credit price is lower.
What happens if a verification comes back unknown?
On bulk jobs and API calls, unknown results are automatically refunded to your balance. You pay for answers, not attempts.
Is there an API?
Yes — one endpoint, API-key auth, JSON in and out. 1 credit per verification, same engine as the dashboard. See the API docs page for copy-paste examples in cURL, Node, and Python.
How is my lead data handled?
Verification results are stored so you can search and export history. You can delete any record, export everything, or delete your account entirely (with a full data export) from Settings. We never sell, share, or email your lists.