Should I validate email addresses using SMTP commands?
Summary
What email marketers say7Marketer opinions
Email marketer from EmailHippo explains that while SMTP validation may seem like a quick solution, it's often unreliable and can damage sender reputation. They recommend using a dedicated email validation service for better accuracy.
Email marketer from Stack Overflow responds that using SMTP commands to validate emails is unreliable. The user shares that the process might seem valid but could be misleading due to server configurations that accept emails and reject them later.
Email marketer from ZeroBounce explains that SMTP verification techniques aren't reliable, as many servers are configured to accept all addresses initially and filter out invalid ones later. This can lead to false positives and a damaged sender reputation if you send to invalid addresses. You need a solution that will tell you if the account is real, active, and likely to engage.
Email marketer from Hunter.io explains that SMTP validation may not be the best practice as it's not 100% reliable. The best way is by sending a test email and hoping the person interacts with it.
Email marketer from Reddit shares that SMTP validation is an old and inaccurate method. Modern email systems use more sophisticated techniques to prevent abuse, rendering SMTP validation ineffective and potentially harmful to sender reputation.
Email marketer from GMass explains that SMTP validation has limitations and may not provide accurate results. Using SMTP for validation can hurt your IP reputation, therefore use an email verification service.
Email marketer from NeverBounce shares that using SMTP to ping a server might tell you if the server exists, but it doesn't confirm that the email address is active and valid. They recommend using a purpose built validation system.
What the experts say3Expert opinions
Expert from SpamResource explains that using SMTP VRFY or similar commands for email validation can negatively impact deliverability. The article details different email verification methods and their impact on email deliverability.
Expert from Word to the Wise answers the question of address verification. It highlights that using SMTP to verify addresses is an antiquated method. While you might determine if an email server exists, you cannot accurately determine if the email address is valid or in use. The article advises against attempting to verify addresses and damaging your reputation in the process.
Expert from Email Geeks explains that if you're trying to do some sort of email address validation, you should not do that. It's probably not something you need, and if you decide you really do then go talk to, e.g., Kickbox instead.
What the documentation says3Technical articles
Documentation from Mailgun advises against relying solely on SMTP for email validation. They explain that while SMTP commands can confirm if a server accepts mail for an address, they don't guarantee the mailbox's existence or validity. They recommend using a comprehensive email verification API.
Documentation from RFC Editor explains that while SMTP commands could technically be used for verifying email addresses, it's not their intended purpose and can be unreliable. The proper use is for email transmission, not address validation.
Documentation from SendGrid explains that verifying email existence via SMTP 'pinging' is discouraged due to potential inaccuracies and negative impacts on sender reputation. They advise using dedicated email validation services instead.