Email Validation - Single & Bulk

Email Validation in PMTAcore

PMTAcore includes a built-in email validator that checks whether email addresses are real and deliverable. You can validate a single email or upload an entire list for bulk processing.

Requirements

• PMTAcore installed and running on Windows 10/11
• Active internet connection
• Any PMTAcore license (basic validation works on free trial, advanced features require a paid license)
• For bulk validation: a .txt or .csv file with one email per line

Validation Levels

PMTAcore offers two validation levels. You can switch between them in the Validation Settings.

Basic (Fast)

• Email format/syntax check
• MX record lookup (checks if the domain can receive mail)
• Disposable email detection (Guerrilla Mail, Mailinator, Temp Mail, etc.)
• Spamtrap detection
• Typo suggestions (e.g. gmial.com → gmail.com)
• TLD validation

Advanced (SMTP + DNS)

Everything in Basic, plus:

• SMTP mailbox verification — connects to the mail server and checks if the mailbox actually exists
• SPF record check
• DMARC record check
• DNSBL blacklist check — checks if the domain is on known blacklists
• Reverse DNS verification
• Catch-all domain detection — tests if the server accepts any address

Single Email Validation

1. Open PMTAcore and click Email Validator in the sidebar.
2. Type or paste an email address in the input field at the top.
3. Click Validate.
4. The app runs all checks based on your selected validation level and shows the result.

Bulk Validation

1. Go to Email Validator from the sidebar.
2. Click Upload List.
3. Select your .txt or .csv file. The app loads the file and shows the total email count and any duplicates found.
4. Click Start Validation.
5. The validator processes emails in parallel (number of threads is configurable in settings). You see real-time progress as each email is checked.
6. When done, click Export to download results.

Understanding Results

Each email gets a status and a quality score (0-100):

• Valid (green) — The email exists and the mail server confirmed it can receive messages.
• Invalid (red) — The email does not exist, the domain has no mail server, the format is wrong, or it is a known disposable address.
• Risky (yellow) — The email might work but there is uncertainty. Usually means the domain is a catch-all server or the SMTP check was inconclusive.

The quality score factors in all checks — syntax, MX, SMTP response, blacklist status, SPF/DMARC, and more. Higher score means more confidence the email is deliverable.

Export Options

After bulk validation, you can export results to CSV with detailed columns including email, status, quality score, issues, warnings, and info messages. You can also export filtered lists — valid only, invalid only, or risky only.

Important Notes

• Some providers like Microsoft (Hotmail, Outlook, Live) and Apple (iCloud) block SMTP verification. These emails will show as valid based on MX/DNS checks but mailbox existence cannot be confirmed.
• Gmail and Yahoo may rate-limit verification attempts on large lists. The validator handles retries automatically but it can slow things down.
• If port 25 is blocked on your network (common on home internet), you need to configure an external SMTP relay or authenticated SMTP server in the settings for Advanced validation to work.