Email Verifier

An email verifier (email checker) is a piece of software that checks if a given email address exists, and if it can receive an email you send. Email verifiers run email addresses through multiple tests to accurately assess their validity and existence, and show you a result for each verified email address.

Using an email verifier is important before contacting email addresses you didn't email before, or when it's been a while since you last reached out. This is because wherever you find email addresses—including your own database–they can be:

• Fake,
• Old and obsolete,
• Mistyped,
• Personal as opposed to professional.

Below is a description of all email checks performed by the Email Verifier on every email address:

• Valid format: First, we validate the format of the email address is correct and looks something like email@provider.com.
• Gibberish email address: We check to ensure the address doesn't look like a fake email address. For example, 1e49cs1pb6@company.com doesn't pass the test in most cases.
• Disposable email address: We check if the email address has a domain name used for temporary email addresses.
• Webmail email address: We verify if the email address uses a webmail service like Gmail or Yahoo.
• Presence of MX records: We check if there are MX records on the domain. If there aren't, the email address can't receive any emails.
• Presence of SMTP server: This check is successful if we are able to connect to the SMTP server (indicated in MX records).
• SMTP check: We test the email address and see if its server is willing to accept emails for the address (without sending an email.)
• Accept-all domain: We check if the server has a accept-all (catch-all) policy that accepts all the email addresses.
• Accept-all verification: We're able to verify accept-all addresses with several major email providers using a proprietary solution.

No, Hunter's email verification service doesn't rely on sending actual emails to the addresses being verified. Instead, we connect to the recipient's SMTP server to verify the address, and we use our knowledge about the given email domain.

If you recently verified an email address with Hunter's Email Verifier and it was verified as 'valid', then it's safe to use—provided your email server is configured well and your sender reputation is satisfactory. We usually observe a bounce rate lower than 1% for these email addresses. However, email verification can never prevent all emails from bouncing, because the existence and validity of the recipient address is not the only factor.

Yes, you can verify a list of professional email addresses with the Bulk Email Verifier. Hunter will run the same email verifications on your entire email list.

Yes, we offer a free API to all Hunter users. It provides the most flexible way of verifying email addresses. High-volume users can use our Data Platform plans to only pay for email verification, without access to other parts of the platform.

You can integrate Hunter's Email Verifier into your CRM. We have built native integrations with leading platform like HubSpot or Pipedrive, and we can serve nearly every other platform through Zapier automations. For more, browse our Integrations.

Yes, our email checker is free. If you create an account, the Free plan lets you verify up to 100 email addresses per month. If you need more email verifications, review our pricing.

Your online forms can be easily targeted by malicious actors with goals like:

• Making you unintentionally email non-existent mailboxes to cause bounces and blocklisting
• Making you pay more for your email marketing tool by inflating your subscriber count

An email verifier can help you spot fake subscribers and submissions on all your forms. Regular verification (or real-time checks) thus protects your organisation from abuse.

Negative consequences of contacting an email address that you didn't verify include:

• Your email can bounce. Every bounced message harms your sender reputation and prevents other emails you send from landing in the recipient's primary inbox.
• Your message may not reach the intended recipient without you ever knowing, because you don't always receive the bounce-back message.

Email validation checks whether an email address is correctly formatted and appears to follow the syntax rules of email addresses (for example, name@domain.com and not namedomain@.com). It ensures there are no typos, extra spaces, or invalid characters. However, it doesn’t confirm that the address actually exists.

Email verification goes a step further. It checks whether the email address is deliverable—that is, whether it can receive messages. A verifier typically connects to the mail server and simulates sending an email to confirm that the mailbox is active.

In short: validation ensures the email looks correct; verification ensures it exists.

“Email verifier” and “email checker” refer to the same tool providing the same service—a tool that confirms whether an email address is valid and deliverable.

A good verifier (or checker) doesn’t just spot typos; it identifies invalid, risky, and accept-all addresses, helping you maintain a low bounce rate and stronger sender reputation.