Email List Validator (Syntax, MX, Disposable, Role, Typos)

Pre-clean an email list before paying for SMTP verification: syntax, MX, disposable domains, role accounts and typo fixes. $0.30 per 1,000.

Give it your own email list, as a list in the input or as a link to a CSV or TXT file. For each unique address you get the normalized form, whether the syntax is valid, whether the domain can receive mail (MX records), and flags for disposable domains, role accounts (admin@, info@, sales@...) and free providers (Gmail, Outlook...). Common typos like gmial.com or hotmail.con get a suggested correction. Each address ends with a status and the reasons behind it.

It does not connect to any mail server. It cannot tell you that a mailbox exists, and it never claims to.

Who it is for

• Anyone about to send a newsletter or a campaign who wants to remove addresses that will bounce for sure.
• Teams cleaning a CRM export or sign-up form data before importing it somewhere else.
• Developers who want to catch typos like @gmial.com in sign-ups and suggest the fix.

Why there is no SMTP check

Some validators open a connection to the recipient's mail server and start sending a message (RCPT TO) to see if the mailbox is accepted. This Actor does not, on purpose:

• Mail servers and blocklists treat this as address harvesting. The IP doing it gets blacklisted, which hurts everyone who shares it.
• The answers are often wrong. Gmail, Outlook, Yahoo and most company servers accept every address at that stage ("catch-all") or reject unknown senders, so the result says little about the mailbox.
• Outgoing port 25 is blocked on most cloud platforms, so the check would mostly time out.

What you get instead is everything that can be checked reliably from public DNS and the address itself.

What it checks

Check	How
Normalization	Trims spaces, removes mailto: and <>, lowercases, converts international domains to punycode (bücher.de to xn--bcher-kva.de). Duplicates are counted once.
Syntax	Practical RFC 5321/5322 rules: one @, local part up to 64 characters with the usual allowed characters and no leading, trailing or double dots, valid domain labels, a real-looking TLD, 254 characters total. Quoted local parts ("john doe"@example.com) and IP literals are rejected: they are legal but practically never used by real people.
Mail DNS	MX records of the domain on the public resolvers 1.1.1.1 and 8.8.8.8. Without MX, an A or AAAA record counts as the mail server, as RFC 5321 says, but the address is marked risky because almost every real mail domain publishes MX. A null MX (0 ., RFC 7505) means the domain accepts no mail. Each domain is looked up once per run.
Disposable	The domain, or a parent domain, is on the disposable-email-domains list (about 10,000 domains, CC0 1.0 public domain).
Role account	The local part (before any +tag) is a shared mailbox name such as admin, info, sales, support, contact, noreply, billing, hr, webmaster or postmaster.
Free provider	The domain is a public mailbox provider such as gmail.com, outlook.com, hotmail.com, yahoo.com, icloud.com, proton.me, gmx.de or mail.ru. This is only a flag, it does not change the status.
Typo suggestion	The domain is one edit away (a missing, extra, wrong or swapped letter) from a popular mailbox domain, after fixing an ending that is not a real TLD (.con, .cmo, .comm, .nett, .ogr...). Examples: gmial.com, gmai.com, hotmial.com, yaho.com, outlok.com, gmail.co, company.con (suggests company.com).

Status

Status	Meaning	Reasons that lead to it
invalid	Will bounce. Remove it.	syntax:<what is wrong>, domain_not_found, no_mail_server, null_mx
unknown	DNS did not answer (timeout or server failure). Try again later. Not charged.	dns_error
risky	Syntax and domain are fine, but there is a reason to be careful.	disposable_domain, role_account, possible_typo, no_mx_a_record_fallback
valid_syntax_and_domain	Syntax is valid and the domain receives mail. The mailbox itself was not checked.	none

The first matching row wins, in the order of the table. A typo domain that does not exist (gmail.con) is invalid and still gets the suggestion. A typo domain that exists (some are registered by typo squatters) is risky.

Input

{
    "emails": ["someone@gmail.com", "info@example.com", "user@gmial.com", "test@mailinator.com"],
    "sourceUrl": "https://example.com/my-list.csv"
}

• emails: a list of addresses.
• sourceUrl (optional): a public link to a CSV or TXT file, up to 50 MB. Every value that contains @ is read, from any column, so a CRM export works as is. Both inputs can be combined.

Output

One dataset item per unique address:

{
    "input": "synthetic.typo003@gamil.com",
    "email": "synthetic.typo003@gamil.com",
    "domain": "gamil.com",
    "syntaxValid": true,
    "isRole": false,
    "isFreeProvider": false,
    "isDisposable": false,
    "suggestedDomain": "gmail.com",
    "reasons": ["possible_typo"],
    "suggestion": "synthetic.typo003@gmail.com",
    "hasMx": true,
    "mxHosts": ["mail.gamil.com"],
    "status": "risky",
    "occurrences": 1
}

occurrences is how many times the address appeared in the input. For an address with invalid syntax only email, domain (null), syntaxValid, reasons and status are filled.

Privacy

The list is read from your input, checked in memory and written only to the dataset of your run. Nothing is stored anywhere else, nothing is sent to third parties (only the domain names are looked up in public DNS), and addresses are not written to the log. The dataset follows your Apify data retention settings and you can delete it at any time.

Speed

A test run with 2,000 synthetic addresses on 72 domains took under 4 seconds with 256 MB of memory. Lists usually repeat a few domains many times, and each domain is looked up only once.

Pricing

Pay per event: email-checked, once per unique address in the dataset. Duplicates and empty lines are not charged, and neither are unknown results. The price is shown on the Actor page. You can cap the cost of a run with the "Maximum cost per run" setting; the Actor stops cleanly when it is reached.

Limitations

• It cannot tell if the mailbox exists or is full. A valid_syntax_and_domain address can still bounce.
• Catch-all domains are not detected, since that needs SMTP.
• The disposable list is maintained by volunteers. New throwaway domains appear every day, and a few typo-squatting domains (for example gmial.com) are on the list too, so they show as both disposable and typo.
• Typo suggestions only cover popular mailbox domains and fake TLDs. A typo in a company domain (acme.com vs acne.com) is not caught.
• Role account detection works on the name only. info@ at a one-person business may well be read by a person.

Refreshing the disposable list

The list is bundled in my_actor/data/disposable_domains.txt and updated with each new build of the Actor:

curl -L -o my_actor/data/disposable_domains.txt \
  https://raw.githubusercontent.com/disposable-email-domains/disposable-email-domains/main/disposable_email_blocklist.conf
python -m unittest discover -s tests -t .
apify push

Run locally

python -m venv .venv
.venv/Scripts/pip install -r requirements.txt   # on Linux/macOS: .venv/bin/pip
# put input in storage/key_value_stores/default/INPUT.json
.venv/Scripts/python -m my_actor
python -m unittest discover -s tests -t .

Author: Matias Isnard.

FAQ

Does it check that the mailbox exists? No. There is no SMTP check, so a valid_syntax_and_domain address can still bounce. The README explains why.

What is charged? Each unique address. Duplicates, empty lines and unknown results are free.

Does it detect catch-all domains? No, that needs SMTP.

Are typos in company domains caught? No. Typo suggestions cover popular mailbox domains like gmail.com and fake TLDs.

Related tools

• Domain Security & Email Deliverability Checker: check SPF, DKIM and DMARC of your sending domain.
• Website Technology Detector: see the email provider and tools of company domains.