Clean the list
Up to 20,000 addresses. Everything runs on your device; the MX check sends only domain names to a public DNS resolver.
How it works
Extract
Addresses are pulled out of whatever you paste — a plain list, a CSV with other columns, or a copied spreadsheet. Up to 20,000.
Normalise
Lower-cased, trailing dots stripped, Gmail dots and +tags collapsed if you tick the option, common typo domains corrected.
Classify
Each address is tested for syntax, then against role, free-mail and disposable lists. Duplicates are caught after normalisation.
MX
Every unique business domain is checked for MX or A records over DNS-over-HTTPS. Dead domains and null-MX domains are removed. Then export.
What a browser can and cannot clean
About a third of a raw export is removable without asking anyone: duplicates from merged sources, addresses with typos in the domain, role mailboxes, disposable providers, domains that no longer exist. This tool does that third, on your device, in a few seconds. What it cannot do is tell you whether priya@acme.co is a real mailbox, because that needs an SMTP conversation with Acme's mail server, and browsers cannot open port 25. The email verifier does it one address at a time; at list scale it is a job for a service.
Why the removals matter more than the count
Hard bounces above about two percent of a send is where Gmail and Microsoft start treating the sender as careless. A raw export with dead domains and typo addresses will bounce at five to ten percent, and one campaign at that rate costs more reputation than the leads were worth. Role addresses are worse in a quieter way: info@ goes to a shared queue where "unsubscribe" is one click and "report spam" is the next one, and some of them are recycled into spam traps. Removing them is a default here for that reason.
Free-mail is a judgement call
The option is off by default because it depends on what you sell. For B2B outreach, a Gmail address in a lead list is usually a personal account scraped from somewhere, and the reply rate is close to zero. For anything consumer-facing, it is the list. The tool keeps them and marks them so you can decide; the export includes the flag.
Twenty addresses at one company
The top-domains table exists for one warning: when a single company domain has twenty or more addresses in a list, the sending tool will happily send all twenty in an hour. That looks, to that company's Google Workspace or Microsoft 365 tenant, exactly like an attack, and the tenant-level block that follows takes every future message from your domain with it. Spread accounts like that across days and inboxes, or cap them at a handful of contacts.
Frequently asked questions
Is this a real email verifier?
It is the half of verification that can be done without contacting the mail server: syntax, duplicates, role, disposable, free-mail, typo domains and MX. Mailbox existence and catch-all detection need SMTP — use the email verifier for single addresses or a bulk service for lists.
Does my list leave my computer?
No. Parsing and classification run in your browser. The optional MX check sends only domain names, not addresses, to Cloudflare's or Google's DNS resolver.
Why are Gmail dots and plus tags treated as duplicates?
Gmail ignores dots in the local part and everything after a plus sign, so j.smith@gmail.com, jsmith@gmail.com and jsmith+news@gmail.com are one mailbox. Untick the option if you want them kept apart.
What counts as a role address?
Local parts like info, sales, support, admin, hello, billing, hr and jobs — shared mailboxes read by a team or a ticket system rather than a person. The list is about eighty of them.
How accurate is the disposable list?
It covers the hundred or so providers that account for almost all disposable addresses in real lists. New ones appear weekly; a bulk verifier with a live list will catch the rest.
Last reviewed
What to run next
The checks that most often follow this one.
More in this category
Guides that go deeper
When the tools tell you something is wrong
The diagnostics here are free and always will be. When the fix is bigger than a DNS record, this is the work I do.
Deliverability rescue
Mail landing in spam, replies gone quiet, or a domain suddenly blocked. I find the actual cause rather than guessing, and fix it.
- Authentication and alignment failures
- Blocklist delistings and reputation repair
- Gateway and filter-level blocks
- A written report on what broke and why
Email & sending infrastructure
Sending domains, inboxes, authentication and warmup, built to survive volume instead of burning down in a month.
- Domain and inbox fleets at any scale
- SPF, DKIM, DMARC and tracking domains
- Google Workspace — Silver Partner
- Handover documentation you actually own
Domain, DNS & migration
Changing registrar, mail provider or host without a day of downtime or a week of mail silently failing.
- Registrar and nameserver moves
- Workspace and Microsoft 365 migrations
- MX, SSL and subdomain cutover
- Staged rollout with rollback at every step
Monitoring & retainer
Infrastructure drifts. Records get edited, certificates expire, domains get listed. Ongoing eyes on the fleet.
- Scheduled checks across every domain
- Alerts before your clients notice
- Monthly reporting
- Priority response when something breaks
Start with a call
Bring a domain and the symptom. I will tell you what is actually wrong and whether you need me at all — plenty of people leave that call able to fix it themselves.
Thirty minutes, no pitch
We will run the checks together on your actual domains, and you will leave knowing what is broken, what it takes to fix, and what it should cost. If that is a job you can do in-house, I will say so.