Check one address
Type it in and get a verdict in seconds.
Mailcleaner guide · Updated 5 November 2026
How do you verify an email address without sending an email?
To check whether an email address is real without emailing it, confirm the format, look up the domain's MX records, then ask its mail server whether the mailbox exists (an SMTP check). An email verifier such as Flaxxa Mailcleaner does all of this in one step and also flags disposable, role and catch-all addresses.
No credit card
Free plan
Cancel anytime
flaxxa.com / product / mailcleaner / features
Capabilities
Everything Mailcleaner ships with.
◉
Layered checks
◇
Risk and confidence
✦
Bulk list cleaning
⌬
Suppressions and re-checks
◐
Domain audit
▣
API and widget
The full feature list→ Start free
01 / 04
How do you check an email address's format?
Start with the shape of the address: one @, a local part before it, and a domain with a dot after it. Look for obvious typos in the domain, such as gmial.com, hotmial.com or outlok.com. These pass a format check but will never reach the person.
This step is free and catches the easy mistakes, but a perfectly formed address can still not exist.
02 / 04
How do you check a domain's MX records?
MX records tell the internet which servers receive mail for a domain. If a domain has none, nothing sent there can be delivered. You can look them up for free with a DNS lookup tool, or on the command line with nslookup -type=mx example.com.
An MX record proves the domain takes email. It doesn't prove the particular mailbox exists.
03 / 04
What is an SMTP check?
An SMTP check connects to the domain's mail server and begins a delivery: it introduces itself, names a sender, then names the recipient. A server that doesn't know the mailbox usually rejects it at this point, and the check disconnects before any message is sent.
It is hard to do by hand: many networks block outgoing connections on port 25, and some providers refuse checks from unknown servers or accept every address. Verifiers run these checks from servers set up for it and read the answers for you.
04 / 04
When should you use an email verifier?
Check a list
Upload a CSV, TSV, TXT or XLSX file, paste a list or import from Google Drive.
Check at sign-up
Add the widget to your form, or call the API from your own code.
FAQ
How to verify an email address: common questions
Signs include a misspelt domain, a known disposable domain, a domain with no MX records, or a mail server that rejects the mailbox. A verifier checks all of these at once.
Put it to work
Mailcleaner features for this
Email verification
Verify one email address or a whole list: a verdict, a 0–100 risk score and a confidence score for each, from a paste, a file, Google Drive or the API.
The checks
The checks behind each verdict: syntax, typo, disposable and role detection, MX lookup, an SMTP mailbox check, catch-all detection and deeper signals.
API and widget
An email validation API for single checks and batches of 1,000, file uploads and signed webhooks, plus a widget that checks addresses on your forms.
Get started in minutes
Try Flaxxa Mailcleaner free.
Start on the Free plan, no credit card needed.
Free plan · No credit card · Cancel anytime