Real-time SMTP verification, catch-all detection, and an email finder — on a multi-IP infrastructure. Clean your lists, kill bounces, and protect your sender reputation.
One engine that checks syntax, DNS, reputation and the live mailbox — then tells you exactly why an address is good or bad.
We open a real SMTP conversation with the mail server and confirm the mailbox accepts mail — without ever sending an email.
Flag accept-all domains and shared mailboxes like info@ and sales@ so you can decide what to keep.
Block throwaway and temporary mailbox providers that tank deliverability and trip spam traps.
Turn a name + company domain into a verified address using the most common corporate patterns — no email required to start.
Upload lists and process them with concurrency control and per-domain throttling. Export clean CSVs in a click.
One REST call returns clean JSON. API keys, rate limits, caching and a usage dashboard included.
Every address runs through the full pipeline and comes back with a status and a 0–100 confidence score.
RFC-grade format and normalization — catches the obvious before any network call.
Resolve the domain's mail servers, with implicit-MX fallback to A records.
Disposable, role and free-provider heuristics, plus typo suggestions.
Connect to the MX and confirm the mailbox at RCPT — and detect catch-all.
Classify as valid, invalid, catch-all, unknown or disposable with a confidence score.
Every result maps to one of five statuses, with sub-status detail and a score you can threshold on.
| Status | Meaning | Typical action |
|---|---|---|
| valid | Mailbox exists and accepts mail. | Safe to send. |
| invalid | Bad syntax, no MX, or the server rejected the mailbox. | Remove. |
| catch-all | Domain accepts every address — the individual mailbox can't be proven. | Send with caution. |
| unknown | Greylisted, timed out, or temporarily deferred. | Re-check later. |
| disposable | Temporary / throwaway mailbox provider. | Remove. |
Have a prospect's name and company domain but no email? MailCheck generates the most-used corporate patterns, probes the mail server, and returns the address that actually exists.
first_name, last_name, domainA clean REST API with predictable JSON, API keys you manage yourself, per-key rate limits, and built-in result caching so repeat checks are instant and free.
Accuracy comes from how you connect, not just what you check.
Rotate probes across multiple sending IPs with proper rDNS so no single IP gets rate-limited or blocked.
Politeness limits per mail provider keep you under their radar and your IPs in good standing.
Results are cached with a configurable TTL — repeat lookups return in milliseconds and don't burn quota.
Temporary deferrals are surfaced as 'unknown' so you can safely re-check instead of discarding good addresses.
We never send email and never store message content. Only the verification verdict is retained.
Track verifications, monitor bulk jobs in real time, and download clean lists from one place.
Create an account and verify right away. Upgrade for higher volume and dedicated sending infrastructure.
RCPT TO stage — the same handshake a real mail server uses to decide if a mailbox exists. We never send a message, so the recipient sees nothing.Create a free account and verify your first emails in under a minute.