How to Verify Email Address Without Sending an Email

How to Verify Email Address Without Sending an Email

Whether you're sending a cold email campaign or a regular newsletter, the first thing you should do before hitting the “Send” button is to verify the email addresses on your prospect list.

By conducting verification, you clean your email list, filtering invalid and fake email addresses that cause bounces and hurt your delivery rate.

Fortunately, you don’t have to spend a lot of time verifying each email address from your mailing list manually. The whole email verification process can be automated by using the right tools.

In this blog post, we’ll explain in detail why you need to verify email addresses, when to do it, how to verify email addresses without sending an email, and how email verification tools work.

Why do you need to verify email addresses?

There are many reasons why email addresses in your database may be considered invalid.

To make sure there are no invalid email addresses in your database, you’ll need to verify them.

These are the main advantages of verification:

Increased delivery rate

The delivery rate is a metric that indicates how many people received your email.

Delivery rate formula

When you send emails, some of them may bounce and, instead of reaching your prospects’ inboxes, get lost on the way to them.

Hard email bounce

Bounces come in two varieties: soft and hard.

  1. A soft bounce is a temporary issue where an email reaches the recipient’s email server but bounces back undelivered. The most typical reasons are the recipient’s inbox being full, the message file being too large, or the email server being offline.
  2. A hard bounce means your email couldn’t be delivered due to permanent reasons, such as the recipient having an invalid or disposable email address (either the domain name is incorrect, isn’t real, or the recipient is unknown).

    Hard bounces are quite dangerous since they can damage your sender reputation. Moreover, your email account might be listed as spammy or even get blocked by various email service providers.

Email verification can help you ensure your delivery rate is high by preventing both soft and hard bounces.

Protect your reputation

Every email account has a sender reputation score, which is an essential component of your email deliverability.

The higher the score is, the more likely your email will be delivered to the recipient's email address.

There are a lot of factors that impact sender reputation: spam complaints, spam traps, sending history, engagement, and unsubscribes. However, bounce rate is the major one.

If you send emails to an unverified list containing invalid addresses, your emails might end up in the spam folder or be rejected outright.

Email address verification helps to keep your email account healthy and enables you to maintain a high sender reputation score.

You can quickly check your email sender reputation using one of these tools to understand where you stand at the moment:

When do you need to verify email addresses?

For each new list of email addresses you get, you’ll need to perform bulk email verification before launching your campaign to ensure your list contains only valid email addresses.

You should validate email addresses every time you use email lookup services or get a list of email addresses from any other external source.

For marketing newsletters, you should verify email lists regularly. The frequency depends on your list and how fast it’s growing. The faster the growth is, the more frequently you should verify it.

You can create a verification schedule and set up notifications in your calendar, so you remember to clean your list regularly.

If you notice that your newsletters’ bounce rate is higher than 2%, you should immediately verify the email addresses on your list. Continuing to send emails to a list of unverified email addresses will damage your sending reputation and decrease the deliverability of your future sends.

Acceptable vs. risky bounce rate

A more technical way to verify email addresses on the fly is to run real-time verification via Hunter's API.

You can integrate the API at many different points of the customer journey to collect higher-quality, deliverable, and valued email addresses in real-time.

This method could be implemented for your opt-in forms, event registration, and other business forms.

How to verify email address without sending an email?

Sending an email to verify someone’s email address can potentially hurt your sender reputation and deliverability. You never know how many emails will bounce. The safest way to verify email addresses is to use email verification tools like Hunter's Email Verifier.

It performs email address validation on multiple levels: format, domain information, the response of the mail servers, and comparison with our unique base of over 100 million professional email addresses.

To verify one or multiple email addresses, simply enter it here and get a result instantly.

Email Verifier screenshot

To verify a list of email addresses, you can use the Bulk Email Verifier.

In this case, you'll need to enter the list of email addresses manually or upload a .TXT or .CSV file.

Hunter Bulk Email Verifier

Once your list is verified, you can download it and check the verification status of each email address on the list.

Results of email verification

How can I be sure an email is deliverable?

A typical .CSV or .TXT file you download after the verification contains several columns. The column to check regarding whether a particular email address is valid is what we call at Hunter the verification status.

CSV file with verification statuses

Let’s take a look at the most common email verification statuses and what they mean:


This means the email passed all the verification checks. The email server exists, and the tested email address can receive emails.

We also made sure the server is not accept-all so you can be confident the email address exists (more about the accept-all status below).

You can use these email addresses safely.


The “Invalid” status means the email address simply cannot receive emails.

The email server might exist (MX records are present), but the particular email address tested doesn’t work. The emails sent to the email address will bounce.

You should avoid sending any emails to an invalid email address.


Accept-all is a server configuration that allows receiving emails to a particular domain even if an email address associated with that domain doesn’t exist.

An accept-all configuration is commonly used by small businesses that want to ensure they receive all emails that are sent to them (regardless of typos) and by big companies to prevent unsolicited emails.

Should you email accept-all email addresses?

Since there is no precise way to determine whether they're valid or not, you need to assess the quality of your list and the risk you can expose yourself to.

Here are a few things to consider when making your decision:

  • The size of your list – If you have a list of just 50 prospects (with about 30% being accept-all email addresses), you can try to email them all. But for larger lists of a few hundreds or thousands of prospects, you might face deliverability issues.
  • The value of your leads – The level of risk you can opt into also depends on how you value each lead on your list. You can consider taking on a higher degree of risk if each lead has a high potential value for your business.
  • Your ESP’s tolerance – Depending on the service you’re using to send emails, you might face limitations if your bounce rate increases. Make sure you know the rules and adapt the quality of your list before sending out any emails.
  • The invalid rate of email addresses on your list: It's often estimated that the bounce rate of accept-all email addresses tends to be about half of the invalid rate of your list. For example, if you have 10% invalid email addresses on your list, the accept-all email addresses will have a bounce rate of 5%.
  • The bounce rate you've already observed with a part of your list If you've started to send emails to your list, you can follow the results and adjust along the way if necessary.

Depending on your situation, you can choose to remove the accept-all email addresses to have the lowest possible risk or keep them on your list.

What if there was a way to keep only the most likely accept-all email addresses?

This is where Hunter’s confidence score comes in.

When you find or verify an email address with Hunter, it also returns a confidence score. This is our estimation of the probability that the email address is accurate.

Hunter confidence score

When you run the Bulk Email Verifier, you get a score for each email address. To keep only the highest quality email addresses and retain a good deliverability rate, you can filter using this score. We recommend keeping the email addresses with a score higher than 80%.


You may see an “unknown” status when Hunter fails to verify an email address.

As you did for the accept-all email addresses, you need to assess the risk to decide whether you will use these email addresses. However, the bounce rate of unknown email addresses is generally higher because, unlike accept-all email addresses, the existence of the SMTP server hasn’t even been proven.

If you've used Hunter and have confidence scores, you can use them to keep only the best email addresses. If you don’t have such a score, we recommend having a rather strict approach for these email addresses or removing them altogether.

How do email verification tools work?

The email verification is complex and consists of multiple steps. Different verification services have different steps and methods—however, these ones would be the starting point for most verification tools:

1. Syntax and formatting check

A syntax and formatting check is typically the first step for most verification services. During this step, it’s possible to see if the email address is spelled correctly and has no extra characters like dots, an extra @ sign, semicolons, apostrophes, commas, etc.

For example, irina@hunter@io wouldn’t pass the test.

2. Domain check

During the domain check, verification services make sure the domain tied to the email address exists, is registered, and works correctly.

This step is essential since sometimes domains expire, and some companies migrate to different domains and create new email addresses tied to them.

At this point, the verification service checks the DNS records for the domain name and MX records to ensure that it can receive emails.

3. Email ping

At this step, email verification services use the SMTP protocol to ensure that the mailbox exists and can receive emails.

After pinging, the server response could be negative or positive. You can safely send email addresses if the response is positive. A negative response means the email address doesn’t exist.

Wrap up

Whether you're sending a regular newsletter or a cold outreach campaign, you should make sure all of the email addresses on your list are valid. This will help increase your delivery rate and protect your sender reputation.

Since verification is something you should do regularly, using an email verification tool would be your best bet to automate this work and run everything on autopilot.

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Irina Maltseva
Irina Maltseva

Previously Head of Marketing at Hunter. I enjoy working on inbound and product marketing strategies. In my spare time, I entertain my cat Persie and collect airline miles.