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Direct Mail:Email address validation

Last Updated:Jan 31, 2026

What is Address Validation?

Email address validation systematically checks each address in a mailing list before you send an email. It uses technical methods and professional algorithms to confirm that an email address is valid, correctly formatted, and can accept emails. It helps email marketers identify and remove invalid, risky, or low-quality email addresses. This ensures your emails are delivered safely and efficiently to the intended recipients.

What capabilities does the Address Validation Service support?

The email address validation service combines several technologies and detection mechanisms to provide highly accurate results:

Supported capabilities

Description

Purpose

RFC-compliant address check

Validates whether an email address complies with the format specifications of RFC 5322 (Internet Message Format) to ensure correct syntax.

Blocks email addresses with obvious format errors, such as user@ or user@.com. This prevents hard bounces from the mail system during the sending process.

Typo check

Detects potential typos in email addresses through contextual analysis and dictionary matching, such as exmaple.comexample.com.

Identifies user errors made during registration or input. This avoids sending emails to non-existent addresses and reduces the bounce rate.

MX record existence check

Verifies whether the email domain has a configured Mail Exchange (MX) record.

Identifies whether the recipient's domain can accept emails. This prevents sending to domains that do not have a mail server configured.

Free email detection

Identifies whether an email address is from a free email service provider, such as Gmail, Yahoo, Outlook, qq.com, or 163.com.

Helps distinguish between corporate and personal email addresses, for example, in B2B validation scenarios.

Disposable address check

Checks whether the email address is a temporary mailbox.

Prevents spam user registration or fake account creation. It improves the quality of user sign-ups and ensures users are real and willing to engage long-term.

Catch-all address

Identifies whether an email address belongs to a catch-all domain. Servers for these domains accept all emails sent to the domain, even if the specific user mailbox (the part before the at sign) does not exist.

Avoids sending to invalid catch-all mailboxes. This improves email accuracy and reduces resource waste.

Some service providers with catch-all domains include qq.com, mail.ru, and Microsoft 365 mailboxes (depending on whether the catch-all feature is enabled for the domain).

The following features currently support detection only for some email service providers (ESPs), such as Gmail, Outlook, Yahoo, Tencent, Netease, iCloud, Proton, Zoho, GMX, Web.de, Mail.com, Mail.ru, Kakao, Naver, Nate, GoDaddy, Namecheap, Yandex, Mimecast, Proofpoint, Barracuda, Cisco, Trend Micro, and Symantec. Support for other ESPs will be added later.

SMTP probe

Verifies whether an email address is valid by simulating a Simple Mail Transfer Protocol (SMTP) interaction.

Directly verifies whether the user part of the email address exists and can accept emails. It effectively identifies hard bounces (such as user not found) and some soft bounces (such as mailbox full or disabled). This significantly reduces the bounce rate during the sending process.

Spam trap check

Detects whether an email address is a recycled spam trap. This prevents triggering anti-spam mechanisms.

Avoids getting blacklisted by email service providers for sending to a spam trap.

Note

For supported ESPs, the validation may still return `Unknown`. This can happen because of insufficient system resources or an error from the recipient's server. Records with an `Unknown` result are not billed.

How do I use the address validation service?

Our email address validation service is available primarily through an API operation. This lets you seamlessly integrate the service into your existing systems, applications, or workflows. You can call the API to retrieve real-time validation results for email addresses. The service supports validation for single or batch email addresses.

For instructions on using the console, see Address validation in the console.

For more information about API operations and examples, see How to use the email address validation API operation?

Billing method

Each validated email address is counted as one check. If the validity of an email address cannot be determined (the result is `Unknown`), the check is not counted. Each Direct Mail instance comes with a free trial of 10 checks.

To purchase the service, go to the Direct Mail console. On the Overview page, find the Email Validity Check section and click Purchase Service.

The pricing for the email address validation feature is as follows:

Specification (Quantity)

Total Price (USD)

10,000

70

30,000

180

50,000

275

100,000

500

200,000

800

500,000

1,750

1,000,000

3,000

Note

For a description of the email address statuses returned by the validation, see Validate email addresses.