Hunter finds emails. InboxCheck verifies them.
Hunter.io is excellent at guessing email addresses from domain patterns. But guessing is not verifying. InboxCheck performs a full SMTP-level check on every address so you know whether it is actually deliverable before you hit send.
Install free Chrome extensionWhy use InboxCheck alongside Hunter?
Short answer: Hunter is an email finder. It scans a company domain and predicts the most likely email pattern (first.last@company.com, f.last@company.com, etc). That pattern matching is very useful for building prospect lists, but it cannot tell you whether a specific mailbox actually exists on the mail server.
InboxCheck picks up where Hunter leaves off. After you have the email address, InboxCheck connects to the recipient mail server and performs a real SMTP handshake to confirm the mailbox is active. This is the difference between guessing and knowing.
For SDRs sending 50 to 200 cold emails per day, this distinction matters enormously. Even a 5% invalid rate on a 1,000-email campaign means 50 hard bounces, which is enough to trigger spam filters on Google Workspace and damage your sender reputation for weeks.
Core focus comparison
Four steps to verified outreach
Install the extension
Add InboxCheck from the Chrome Web Store. It takes about ten seconds.
Browse normally
Open LinkedIn, Apollo, Hunter, or any website where you find prospect emails.
Click verify
A small button appears next to every email address on the page. Click it.
Read the verdict
InboxCheck returns Safe, Risky, or Unsafe in under two seconds. Decide whether to send.
The real cost of sending to unverified emails
Every email service provider tracks your bounce rate. Google Workspace, Microsoft 365, and most SMTP relays will flag your domain if your hard bounce rate exceeds 3%. Once flagged, your future emails route directly to spam, even the ones going to perfectly valid addresses.
Recovering from a damaged sender reputation takes weeks of careful warm-up. During that recovery window, your entire outbound pipeline stalls. For a sales team running time-sensitive campaigns, that downtime translates directly into lost revenue.
Hunter does an excellent job of predicting email addresses, but prediction is not confirmation. People change jobs, companies restructure domains, and mailboxes get deactivated. Our 2026 Data Decay Audit found that 18.4% of B2B prospect emails from major data providers were invalid at the time of testing.
The solution is straightforward: verify every email before it enters your outbound sequence. InboxCheck makes this effortless because the verification happens inside your browser, right where you are already doing your research.
Frequently asked questions
Is InboxCheck a direct Hunter.io replacement?+
Not exactly. Hunter.io is primarily an email finder that guesses email addresses from domain patterns. InboxCheck is a dedicated email verification tool. Many sales reps use both: Hunter to find the address, then InboxCheck to verify it is actually deliverable before sending. If you already have the email and just need to confirm it works, InboxCheck replaces the verification step entirely.
Can I verify emails found by Hunter using InboxCheck?+
Yes. After Hunter suggests an email address, you can verify it instantly using InboxCheck without leaving the page. The extension detects email addresses on any webpage and adds a verify button next to each one. One click tells you whether the address is Safe, Risky, or Unsafe.
How accurate is InboxCheck compared to Hunter's built-in verification?+
InboxCheck runs a full SMTP handshake, MX record lookup, SPF/DMARC validation, catch-all detection, and disposable domain filtering for every single verification. Hunter's verification is a secondary feature layered on top of their email finding engine. Because verification is our only focus, we catch edge cases that bundled tools typically miss.
Does InboxCheck offer a free plan?+
Yes. Every InboxCheck account includes a free daily allowance of verifications. You do not need a credit card to start. Sign up, install the Chrome extension, and begin verifying emails immediately. If you need more capacity, paid plans start at a few dollars per month.
What does InboxCheck check when verifying an email?+
Each verification runs five checks: syntax validation to catch typos, DNS and MX record lookup to confirm the domain accepts email, a live SMTP handshake to test whether the specific mailbox exists, catch-all detection to flag domains that accept everything, and disposable address filtering to identify throwaway inboxes. The result is a clear verdict: Safe, Risky, or Unsafe.