How to Verify Email Address Without Sending an Email

How to Verify Email Address Without Sending an Email

Whether you are sending a cold email campaign or a regular newsletter, the first thing you should do before hitting a “Send” button is to verify the list of your emails.

By conducting verification, you clean your email list, filtering invalid and spammy 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 process can be run on autopilot.

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?
When do you need to verify email addresses?
How to verify email address without sending an email?
How can I be sure an email is deliverable?
How do email verification tools work?

Why do you need to verify email addresses?

There are many factors why emails in your database may be considered invalid. Some reasons are technical—others are human factors.

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

These are the main advantages of the verification:

Increase delivery rate

The delivery rate is the 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 typically have two types: 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 is full, the message file is too large, or the email server is offline.
  2. A hard bounce means your email couldn’t be delivered due to permanent reasons, such as the recipient’s email address is invalid (either the domain name is incorrect, isn’t real, or the recipient is unknown).

    Hard bounces are quite dangerous since they degrade the email account’s authenticity and domain quality. 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 eliminating bounces, both soft and hard.

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 an Internet Server Provider (ISP) will deliver emails to your prospects’ inboxes.

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

If you send emails to an unverified list containing spammy or invalid emails, the ISP may send your emails to spam folders or even reject them outright.

Verification of email addresses helps to keep your email account healthy and 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:

Get clear outreach metrics

Once you verify an email list, you’ll have only email addresses that are valid and deliverable. It will be easy to analyze your email campaign stats and data since you know that the list is accurate.

Let’s say you noticed a low open rate for your email campaign. With a verified list, you can be sure that there was a problem with your subject line, and for the next test, you can modify it to expect better results.

When do you need to verify email addresses?

For each list of new emails you get, you’ll need to run a bulk email verification before reaching out to those prospects.

You should do this every time you collect email addresses from email lookup services or get a list of emails from any other external sources.

For marketing newsletters, you should run verifications 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 as not to forget to clean up your list regularly.

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

A more technical way for verification is to run real-time verification via the API. You can integrate an 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.

Such tools allow you to verify emails in a matter of seconds. For example, Hunter’s Email Verifier performs such validations on multiple levels: format, domain information, 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.

Hunter Email Verifier

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

In this case, you need to enter the list of email addresses manually or upload a .txt or .csv file.

Hunter Bulk Email Verifier

Once your emails are verified, you can download the list and check their verification statuses.

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 exactly they mean:


This means the email passed all of 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 email addresses.

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.

Don’t use these email addresses.


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 use accept-all emails?

Since there is no precise way to determine whether they are 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 look at to make 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, you might face deliverability issues.
  • The value of your leads: Of course, the level of risk you can opt into also depends on how you value each lead in your list. You can consider taking on a higher risk if each lead has a high value to 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.
  • The invalid rate of email addresses in your list: It is often estimated 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 in your list, the accept-all email addresses will have a bounce rate of 5%.
  • The bounce rate you have already observed on a part of your list: If you have started to send emails with your list, you can progressively 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 keep the lowest possible risk, or keep them in your list.

What if there were 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, 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 (or another email verification service) 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 proved.

If you 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?

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

1. Syntax and formatting check

Syntax and formatting check is typically the first step of validation 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, at sign, semicolons, apostrophes, commas, etc.

For example, irina@hunter@io doesn’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 emails tied to them.

At this point, the verification service checks the DNS records for the domain name and MX (mail exchanger) 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 are sending a regular newsletter or a new cold outreach campaign, you should make sure all of the emails in your list are valid. This will help you increase your delivery rate, protect your sender reputation, and present you with clear outreach metrics.

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

While choosing a verification tool, explore the verification process and which checks the email is typically running through. So, in the end, you can get a clean and verified list that you can use for outreach safely.

Have questions or feedback? Don’t hesitate to ping me on Twitter or at

Irina Maltseva
Irina Maltseva

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

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