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/ Free Tools — Email List Hygiene

See the ballast dragging your list down.

Paste a list and clean it in your browser: syntax, live MX lookups, disposable domains, role addresses, duplicates, and typo fixes like gmial.com. A quality meter fills by category so you see the deliverable fraction in seconds — nothing uploaded.

Request infrastructure review What it catches

Syntax, disposable, role, typo, and duplicate checks run in your browser; only domain names go out for the MX lookup. Up to 300 addresses per run.

/ What this does

A dirty list is what quietly pushes a sender past the Gmail and Yahoo complaint thresholds: dead domains, disposable inboxes, role addresses, and mistyped domains that bounce or never engage. This tool grades a pasted list against every problem you can catch without sending mail — syntax, a live MX lookup per domain, disposable and role detection, duplicates, and typo domains with the fix suggested — and fills a quality meter by category so you can see the deliverable fraction emerge as it processes. It's honest about the one thing a browser can't do: confirm a specific mailbox exists, which needs an SMTP check. Everything else, it catches.

Domains are de-duplicated before the MX lookup, so a list dominated by Gmail resolves in a handful of queries, and only domain names ever leave your browser. The breakdown lets you act with a scalpel: drop the disposable and invalid, fix the typos into recovered subscribers, and decide on role addresses by send type. Each result carries the reason it was flagged, so cleaning is a decision, not a guess.

  • Six checks

    Syntax, MX, disposable, role, duplicate, and typo — the full set of problems catchable without sending a message.

  • Live MX

    Each unique domain checked against DNS for mail records — de-duplicated, so big lists resolve in a few queries.

  • Typo fixes

    gmial.com and its cousins caught by edit distance and corrected — recovered subscribers, not discarded ones.

  • Nothing uploaded

    Only domain names go out, for the MX lookup. Addresses and the list never leave your browser.

/ What it catches

What actually makes an address bad?

Bad addresses come in tiers, and the tool sorts them so you can treat each differently. The hard rejects are addresses that are provably undeliverable: malformed syntax that no mail server would accept, and disposable domains — the temporary inboxes people use to slip past a signup and then abandon. These add nothing but bounces and complaints, so they come off the list.

Then there's the domain-level signal: a missing MX record. If a domain publishes no mail servers, it almost certainly can't receive mail, so those addresses are undeliverable at the domain level regardless of how clean the local part looks. This is the one check that touches the network, resolved live per unique domain.

The rest are risks rather than rejects. Role addresses like info@ and support@ are valid but draw low engagement and higher complaints, so they belong in transactional mail and usually not in marketing. Duplicates waste sends and can trip frequency limits. And typo domains — a Gmail address a hair off from correct — are the most recoverable of all: rather than lose the subscriber, the tool hands you the likely fix. The one thing left, whether a live mailbox sits behind a valid domain, is the province of an SMTP check a browser can't perform, so the tool says so instead of guessing.

/ The real fix

Why is cleaning a list a symptom, not a cure?

Cleaning is worth doing, and it's also treating the wound after the fact. Every bad address on a list got there somehow — a signup form with no validation, a checkout that accepted a mistyped domain, an import from an old spreadsheet no one vetted. Clean the list today and it drifts dirty again, because the intake is still open. The durable fix is to validate at the point of capture, so a malformed address is caught before it's saved and a typo is corrected while the person is still on the page to confirm.

This matters more under the 2026 rules than it used to. A high bounce rate on a new send tells Gmail and Yahoo you don't know your own audience, and complaints from disengaged addresses push you toward the 0.3% ceiling that gets mail rejected outright. A list kept clean at the source protects the sender reputation that determines whether your good mail reaches the inbox at all. Building that validation into your forms, your imports, and your sending pipeline — and monitoring the bounce and complaint signals that warn you early — is the ongoing operation behind a healthy program, which is what we run.

/ Hygiene FAQ

What does this catch, and what can't it?
It catches everything you can check without sending mail: malformed syntax, domains that can't receive mail (no MX record, checked live), disposable and throwaway domains, role-based addresses like info@ and support@, exact duplicates, and typo domains such as gmial.com or hotmial.com with the correction suggested. What it can't do — and won't pretend to — is confirm that a specific mailbox exists behind a valid domain. That last step requires an SMTP conversation with the receiving server, which a browser can't make. So this is honest list hygiene, not mailbox verification: it removes the addresses that are provably bad and flags the risky ones, which is the majority of what damages a list.
Why do role-based and disposable addresses matter?
They hurt deliverability in different ways. Role addresses — info@, sales@, admin@, noreply@ — often reach a shared mailbox or none at all, draw low engagement, and attract more complaints, which is why many senders exclude them from marketing sends even though they're syntactically valid. Disposable domains are temporary inboxes people use to dodge signup; they either stop existing or never engage, so they inflate your list, tank your open rate, and raise your bounce and complaint rates. Both are the kind of quiet ballast that pulls a sender under the Gmail and Yahoo complaint thresholds, so seeing them called out lets you segment or drop them before a send.
How does the MX check work?
For every unique domain in your list, the tool asks public DNS over HTTPS whether the domain publishes MX records — the entries that name the servers accepting its mail. A domain with no MX is very unlikely to receive email, so those addresses are flagged as undeliverable at the domain level. Domains are de-duplicated first, so a list of five thousand Gmail addresses is a single lookup, not five thousand. It's the same signal a sending server uses to decide where to deliver, resolved live in your browser.
How does the typo detection work?
It compares each domain against the big consumer providers — Gmail, Yahoo, Hotmail, Outlook, iCloud, and the rest — using edit distance, the number of single-character changes between two strings. A domain that's one or two edits away from a major provider but isn't that provider is almost always a typo: gmial.com, gmai.com, gmail.con, hotmial.com, yaho.com. The tool suggests the correction so you can fix rather than discard the address, because a mistyped Gmail address is a real subscriber you'd otherwise lose. Custom company domains sit far from any freemail domain, so they aren't flagged.
Is my list uploaded anywhere?
No. Parsing, syntax, disposable, role, typo, and duplicate checks all run in your browser, and the only thing that touches the network is the DNS-over-HTTPS MX lookup — which sends just the domain names, the same public records any mail server queries, never the full addresses or the list. Nothing is stored or logged. For a genuinely sensitive list you can confirm in the network tab that only DNS queries go out.
What should I do with the results?
Drop the provably bad — invalid syntax and disposable domains — outright. Fix the typo suggestions, since those are recoverable subscribers. Decide on role addresses by send type: keep them for transactional and support mail, exclude them from marketing. Treat no-MX domains as undeliverable. What remains is a list that will bounce less and complain less, which is what keeps you under the thresholds. For an ongoing program, the real win is validating at the point of capture so bad addresses never enter — which is part of what we set up.

Cleaning is the symptom. Validating at capture is the cure.

A one-time clean helps, but a list drifts dirty again unless the intake is fixed. Building validation into your forms, imports, and pipeline — and watching the bounce and complaint signals — is what we operate. Clean the list, then let's fix the source.

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