The Email Bounce Checker That Catches Hard Bounces.

Yes, and not in the bait-and-switch sense. The pill at the top of this page bounce-tests 4 addresses a day with no account at all, which is enough to sanity-check the handful of contacts you are nervous about before a campaign goes out.

When you need to screen a whole send list, a free signup adds 1,000 bounce checks immediately, or 2,500 if you register with a work address. No card either way. Past that, credits are pay-as-you-go, they never expire, and volume pricing is localized to your region.

Three families of cause cover almost every bounce-back. The mailbox is gone (the person left the company, the account was deleted), the domain is gone (company folded, domain expired, MX records removed), or the message was refused in the moment (full inbox, greylisting, a server hiccup). The first two produce hard bounces; the third produces soft ones.

B2B lists rot fast because people change jobs, which is why a list that was clean a year ago can bounce at 5 percent or worse today. Running a bounce test before each send catches the decay. If your bounces come with spam-block wording rather than unknown-user codes, the problem may be your own domain reputation instead: run an email blacklist check to rule that out.

A bounce is just the receiving mail server telling you, after the fact, that an address is dead. The bounce checker runs the exact handshake the inbox would, without delivering anything, so you get that same verdict before the send instead of as a failure report after. Nine checks run in parallel on every address: syntax and format validation (RFC 5321 / 5322), domain existence and MX-record presence, the SMTP handshake and mailbox-exists ping, disposable-domain match, role-address detection, catch-all domain detection, an AI-confidence pass on catch-all addresses, domain-age scoring, and email authentication signals (SPF, DKIM, DMARC).

The catch-all resolution is the one most free bounce checkers skip, and it’s where 20 to 40 % of B2B email lists quietly bounce. If you just want to check one email at a time, the checker runs the very same engine.

A hard bounce is permanent: the address does not exist, the domain is dead, or the mailbox is closed. A soft bounce is temporary: the inbox is full, the server is down for a moment, or the message is too large.

Hard bounces are the ones that wreck your sender reputation, and they are exactly what this bounce test is built to catch ahead of time. The engine flags dead addresses as invalid so you can suppress them before the send. You can wire the same check into your stack with the API to screen every address at signup or import.

Most teams running a list through Verifox for the first time cut hard bounces from the 5 to 15 % range down to under 1 %. Mailbox providers start throttling and spam-foldering once you cross roughly 2 %, so getting under that line is what protects inbox placement for every send after.

Lower bounce rate means a healthier sender reputation, which means more of your good email actually lands. The accuracy here matches the paid verification engine, so the free tier reduces bounces just as hard as the paid one.

Same engine as the paid plans. 99.99 % accuracy on a 1,000-address benchmark list, including catch-all domains.

The free tier doesn’t trade accuracy for the price tag. It caps volume only. Every check the paid Email Verification API runs to flag a bounce risk is the same check the bounce checker on this page runs.

Yes. The free tier gives you 1,000 checks (2,500 if you sign up with a work email), so you can clean most small lists for bounces outright before a send.

For larger lists, our paid credit packs are pay-as-you-go and never expire, with pricing localized to your region on the pricing page. CSV upload, API access, and bulk parallel processing are included from the free tier up. If you prefer the validator phrasing, the free email validator runs the identical engine on bulk lists.

No. A send list is the most sensitive asset a marketing team uploads anywhere, so we treat it accordingly: every address, single check or CSV upload, is processed in memory and discarded the instant its bounce verdict comes back. We never log it, never warehouse it, and never sell it. Your pre-send list does not become anyone else’s training data or lead source.

The whole pipeline is SOC 2 Type II audited, and the privacy policy spells out exactly what we touch during a check and what we refuse to keep.

That limit exists because pasting a campaign list four addresses at a time is the wrong tool for the job. If you are cleaning a real send list, sign up free: the account unlocks CSV upload plus 1,000 checks on the spot (2,500 with a work email), still with no card on file. That covers most newsletter and outbound lists in one pass.

Otherwise the anonymous limit resets in 24 hours. Teams bounce-testing 10,000+ addresses before every campaign usually buy a credit pack once and draw it down, since credits never expire.

Yes, and real time is the whole point: screening an address the moment it enters your funnel keeps the bounce out of your list instead of cleaning it up later. The REST API returns a verdict in roughly 380 ms median (sub-50 ms cached), fast enough to gate a signup form inline, while bulk jobs stream about 10,000 emails per minute on the standard tier. HubSpot, Salesforce, Zapier, Klaviyo, Mailchimp, and Brevo connect without code.

Uptime is contractual: 99.9 % SLA on Starter and 99.99 % on an annual Volume contract, with live incident history at status.verifox.ai. AI agents skip the glue code entirely via the native MCP server.