# DWM Email Checker

> DWM Email Checker (https://emailcheck.dealwithmuhammad.com) is a free online tool that checks whether an email address exists and can receive mail, before you send to it. It checks the format, suggests fixes for typos, confirms the domain and its mail (MX) servers, flags disposable, role and free-provider addresses, looks for a public Gravatar and SPF/DMARC records, and, where the mail server allows it, asks that server whether the mailbox exists, without sending an email. Each address gets a Valid, Invalid, Risky or Unknown verdict with a 0–100 score and a plain-English explanation. There are no ads and no sign-up. It was built by Muhammad Ahmad, a web and mobile app developer in Kuala Lumpur, Malaysia.

## What it checks

- **Format** — practical RFC 5321/5322 rules: an @ sign, at most 64 characters before it and 254 in total, allowed characters, no consecutive or leading/trailing dots, a valid domain name and ending. Internationalised (IDN) domains such as münchen.de are converted to punycode.
- **Typos** — "Did you mean …?" suggestions for common slips such as gmial.com → gmail.com, hotmial.com → hotmail.com, yahooo.com → yahoo.com, outlok.com → outlook.com and endings like .con or .cmo → .com. One click applies the fix and re-checks.
- **Domain and mail servers** — DNS lookups for MX records; falls back to the domain's own A/AAAA address when there are no MX records (implicit MX); detects Null MX (RFC 7505), which means the domain never accepts email; and detects domains that don't exist (NXDOMAIN).
- **Mail provider** — identified from the MX hosts: Gmail, Google Workspace, Outlook.com, Microsoft 365, Yahoo, AOL, iCloud, Zoho, Proton, Fastmail, Yandex, Mail.ru, GMX, WEB.DE, IONOS, Namecheap, GoDaddy, Titan, Hostinger, Amazon WorkMail/SES, Rackspace, Mimecast, Proofpoint, Barracuda, Cloudflare Email Routing, ImprovMX, Forward Email and others.
- **Mailbox (SMTP check)** — where available, connects to the domain's highest-priority mail server on port 25, sends EHLO, MAIL FROM and RCPT TO for the address, and disconnects with QUIT. It never sends DATA, so no email is sent and the owner isn't notified. Replies are read as: accepted (250/251), mailbox doesn't exist (550/551/553 or 5.1.x), mailbox full (4.2.2/5.2.2), try later (421/450/451/452, greylisting, rate limits) or refused by anti-spam/IP policy (e.g. 5.7.x, Spamhaus). Policy refusals are reported as "couldn't confirm", never as "doesn't exist".
- **Catch-all** — after an accepted address, it also asks about a random address that can't exist; if that's accepted too, the domain accepts all mail and the specific mailbox can't be confirmed.
- **Disposable addresses** — the domain, its parent domains and its mail servers are compared with the community disposable-email-domains blocklist (CC0, nearly 10,000 domains).
- **Role addresses** — info@, support@, sales@, admin@, noreply@, postmaster@, billing@, hr@, jobs@, team@ and similar.
- **Free providers** — Gmail, Yahoo, Outlook/Hotmail/Live, iCloud, AOL, Proton, GMX, Yandex, Mail.ru, Zoho and other free webmail domains.
- **Gravatar** — whether the address has a public Gravatar (looked up by the SHA-256 hash of the address), a strong sign the address is real and in use.
- **SPF and DMARC** — whether the domain publishes SPF and DMARC records (informational).

## Verdicts

- **Valid** — the mail server confirmed the mailbox and doesn't accept every address, or the address has a public Gravatar and its domain accepts email.
- **Invalid** — bad format, the domain doesn't exist, the domain has no mail server or a Null MX, or the mail server rejected the mailbox.
- **Risky** — a disposable address, a catch-all domain (or a server that accepted the address but couldn't be tested for catch-all), a full mailbox, or a role address whose mailbox couldn't be confirmed.
- **Unknown** — the domain accepts email but the mailbox couldn't be confirmed: the mail server refused or deferred the check (common with Gmail, Outlook and Yahoo), the server couldn't be reached, or the mailbox check isn't available on the server running the site.

## Bulk checking

Paste up to 50 addresses (one per line, or separated by commas or semicolons) or upload a .csv or .txt file. Addresses are checked three at a time with a progress bar; results can be sorted and filtered by verdict and exported as a CSV file (email, verdict, score, summary, provider, disposable, role, free provider, catch-all, Gravatar, MX, suggestion, time).

## Privacy

- Email addresses are checked in memory and are never stored or logged on the server.
- Recent single checks are kept only in the visitor's own browser (localStorage) and can be cleared.
- The site records anonymous page views and which feature was used (for example "email-check" or "email-export-csv"), never the addresses.
- No account, no sign-up, no ads.

## Limits

- Fair-use rate limit per visitor: 60 checks per 10 minutes and 300 per day. Bulk runs are capped at 50 addresses.
- The mailbox (SMTP) check needs outbound port 25, which many hosts, including Vercel, block. When it isn't available, results say "Mailbox check isn't available on this server" and the verdict relies on the other checks, so many addresses at real domains show Unknown rather than a guess.
- Big providers such as Gmail, Outlook, Yahoo and iCloud often refuse or rate-limit mailbox checks from unknown servers, so their addresses frequently show Unknown.
- No checker is 100% certain: a confirmed mailbox can still be full, abandoned or filtered later, and catch-all domains can't be checked mailbox by mailbox.

## How to check if an email address exists

1. Open https://emailcheck.dealwithmuhammad.com, type or paste the address and press Check (or Enter).
2. Read the verdict, score and checklist. Open "Technical details" for MX records, SPF/DMARC records and SMTP response codes. Click "Copy result" to copy a text summary.
3. If a "Did you mean …?" suggestion appears, click it to fix the typo and re-check. For a list, switch to Bulk.

## FAQ

- **Does it send an email?** No. The SMTP check stops before the DATA step, so no message is sent and the person isn't notified.
- **Can it check Gmail, Outlook and Yahoo addresses?** Yes, but these providers often refuse to confirm mailboxes, so results may be Unknown, with the reason shown. A public Gravatar can still confirm an address is in use.
- **What does catch-all mean?** The domain accepts mail for any address, real or not, so the specific mailbox can't be confirmed. These results are Risky.
- **Is it free?** Yes — free, no ads and no sign-up, with a fair-use limit of 60 checks per 10 minutes and 300 per day.
- **Are the addresses stored?** No. They're checked in memory and never saved or logged.
- **Who made it?** Muhammad Ahmad, a web and mobile app developer in Kuala Lumpur, Malaysia.

## Author

- Name: Muhammad Ahmad — Web & Mobile App Developer, Kuala Lumpur, Malaysia
- Portfolio: https://www.dealwithmuhammad.com
- Case study: https://www.dealwithmuhammad.com/work/dwm-email-checker
- Email: me@dealwithmuhammad.com
- WhatsApp: https://wa.me/601139865270
- GitHub: https://github.com/Deal-With-Muhammad
- LinkedIn: https://www.linkedin.com/in/muhammad-ahmad-7009b8248/

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