Clean an email list
A list that bounces costs more than one campaign: past a few percent of hard bounces, your sending provider warns you, then suspends you. See what yours contains first — that part is free and never leaves your browser.
The analysis runs in your browser: no address leaves it. Only the domain names of a sample are sent, for the MX test.
How the check works
- 1
The analysis is free and local
Your list is split, de-duplicated case-insensitively, checked against RFC 5322 syntax and matched against known temporary-inbox providers — all on your machine. The file is not uploaded and appears in no log.
- 2
The sample shows you the rest before you pay
Only the domain names of about twenty addresses are sent — never the addresses. You get back how many of those domains have no mail server at all.
- 3
The full check is the paid step
Every domain in the list is queried over DNS. One credit per address checked, with duplicates and broken syntax excluded from the count. This is the step that sends the addresses, and it says so before it runs.
Where the privacy line actually sits
During the analysis, nothing leaves the page — which is exactly why it can be free and account-free. The paid check does send the addresses to our server: querying each domain's DNS cannot be done from a browser, and pretending otherwise would be a lie you would discover later.
Nothing is retained beyond the request: the list is processed and dropped, and only an aggregate line lands in your usage log.
Why duplicates are not billed
Because they cost nothing to process. A 12,000-line list often holds 2,000 duplicates and only a few hundred distinct domains — DNS is resolved per domain, once, not per address. The count shown before payment is the number of addresses actually checked.
Frequently asked questions
What is free and what is paid?
The analysis is free and needs no account: duplicates, broken syntax, disposable domains, all computed in your browser. The paid part is checking each domain's mail server — one DNS query per domain, which a browser cannot make. One credit per address checked, duplicates excluded.
Is my list uploaded?
Not during the analysis. Splitting, de-duplication and disposable detection happen on your machine; only the domain names of a sample are sent. The full check does send the addresses — it is the only way to query each domain's DNS, and it is stated plainly before you start it.
What does 'domain with no mail server' mean?
The domain publishes no MX record and no fallback A record. No mail can be delivered to it: those addresses hard-bounce every time. It is the category that damages sender reputation most, and the one no syntax check can see — 'john@gmial.com' is perfectly well formed.
How many lines can I process?
Up to 50,000 per run. The list is cut into batches of 500 processed one after another with a progress bar; a 12,000-address file takes a few seconds. Beyond that, or to wire the check into a pipeline, the API does the same work from your code.
The same check over API
This tool runs in your browser. To run the same check from your code, in bulk or server-side, the API answers in JSON.
Read the documentation