Understanding how to check if an email is valid is instrumental if you want to be successful in cold email outreach.

Email verification has major impact on your open rate in short term, but on your sender's reputation in the long run too. If you don't check if an email is valid prior to sending someone an email, you're exposing yourself to all kinds of email deliverability trouble.

In this article, you will learn how to make sure your email list is clean and your email reputation remains intact.

Why should you verify email addresses without sending emails first?

The reason we check if an email address is valid without sending the email first, is because of email deliverability and to avoid hurting our domain reputation.

In short, if you send a campaign to invalid email addresses, it will result in a higher bounce rate. If you experience higher bounce rates, your sending score will start to go down. You might even end up being blacklisted.

Bounce rate

An email bounce is any email message rejected by a recipient's mail server and returned to the original sender. To put it simply, you get a bounce if you send a message to a non-existing email.

You might wonder what is an acceptable bounce rate in email outreach?

Our advice is to always keep it under 5%. And in a second we'll show you how to do that. But first, a few more explanations.

๐Ÿ‘‰ Soft email bounce

A soft bounce refers to an email that landed in your recipient's mail server but bounced back undelivered before it got into the inbox.

Numerous reasons can explain this bounce, including that the message was too large for the recipient's inbox, their mailbox was full, the message does not meet the recipient serverโ€™s policies, or the server was temporarily down.

๐Ÿ‘‰ Hard email bounce

A hard bounce happens when the email is permanently rejected because the email address is invalid or the email addresses donโ€™t exist.

This could be as a result of an invalid email address, an outdated domain, or an address that has fallen out of use, and in the worst-case scenario become a spam trap.

Moral of the story?

The "soft" bounce isn't a big deal, but the "hard" bounce is.

๐Ÿ‘‰ Long-term consequences on the outcome of your campaign

Sending hundreds of emails to people you haven't verified previously is a huge trigger for Google and any other email provider. It's super easy for them to identify this behaviour and punish you.โ€Œ

If you act like a spammer, you have a huge chance of damaging your email reputation. The bounce rate is one of the 5 factors affecting your domain reputation.

There's just no common sense in exposing yourself to all these issues and not doing the email verification properly.

How do you check email address validity?

You have multiple options available to check if an email address is valid. For instance, some email lookup tools have built-in verification, so you can argue that it's worth investing money in a reliable email finder.

Most popular are, of course, email verification tools that specialize in this niche. It works pretty simple. You upload your email list on their platform and they deliver you a CSV report that labels undeliverable and risky emails.

Furthermore, you can integrate an email verification tool with your cold email software for a much smoother experience. That way, you don't have to upload your email list two times. You can see how it works between lemlist and Bouncer here.


To check email address validity, these tools perform 3 main types of verification:

  • Syntax check

It checks whether an email address is spelled correctly - has no spaces, commas, and if all the @s, dots, and domain extensions are in the right place.

  • Domain check

It checks the domain and email address on it making sure it works properly.

  • Email ping

Email verification tools send messages to a receiver's server to confirm whether the email address actually exists on the server and if it is active.

Hereโ€™s how to check if an email is valid in 2 ways

If you're still not sure how to check if an email is valid, this is a section where we get more tactical.

First, we'll talk about the more common case where people take care of this in bulk. Afterward, we'll see how to test if an email is valid manually and for free.

Let's dig in.

How to bulk verify email address without sending email out

Searching for the best email verifier tool is not such a difficult task because there are many options in the market to choose from.

In order to check which one is the most popular, we created a poll asking the members of the biggest closed community for salespeople about the email verification tools they use.

On top of that, we tested a bunch of them ourselves.

Here's a list of those who in our opinion are most reliable to do a valid email check.

  • Clearout, starting from $21 for 3000 credits
  • Bouncer, starting from $0.0025 for 1 credit
  • Neverbounce, starting from $0.008 for 1 credit
  • Emailable, starting from $0.004 for 1 credit
  • TheChecker, starting from $0.003 for 1 credit
  • Truemail, starting from $7 for 1000 credits
  • Zerobounce, starting from $0.008 for 1 credit
  • Debounce, starting from $0.002 for 1 credit

You will essentially have to follow the same steps in order to verify your prospective customer's address from a bulk list.

Let's imagine you've picked Bouncer as your go-to verification tool. Here's how the process will look like.

[Step 1] Upload your list

You will have to upload your bulk email database in a CSV file or another flexible format.

[Step 2] Start verification

The tool will clean up the email list in a single click and with precise accuracy.

[Step 3] Analyze stats

Your results will appear with detailed statistics to show soft bounce rates, hard bounce rates, spam traps, etc.

[Step 4] Upload the clean list to your cold email tool

You will be able to download the verified result, which will look something like this according to the tool.

How to check email addresses are valid manually

If you do not want to bulk check emails, we have a quick and easy solution for a manual and valid email address check, which also happens to be free!

Here are the steps to follow:

[Step 1] Use Google Sheets

Very simply, hover over the email in your Google Sheet list and you should be able to see someone's full name and image. Works best if they use Gmail of course.

manual email verification

[Step 2] Use Email Permutator

It's really a close variation of the method mentioned above. Only this time, your going to go to Email Permutator and generate all possible email combinations of someone.

You just input the following data.

manual email verification check

Then, you'll copy/paste all results into your email and simply hover over to see which one results in real data.

free email verification

[Step 3] Use free online tools

When you Google queries like "email checker online free", you'll discover most manual email verification services. An example is Email Checker.

manual email verification check

Key takeaways

In today's world, email outreach requires special focus on ensuring your emails are delivered and opened, in order for your leads to respond. But a lot of users may not be spending the necessary time for this, impacting their bounce rate, affecting their domain reputation, and most importantly, deliverability!

In order to combat this, we have identified two methods to send and verify an email address without sending the email in the first place:

  • Free and straightforward tools such as email-checker.net will verify email addresses one at a time, which is perfect if you send only a few outbound emails on a weekly basis.
  • Conversely, a paid email verification tool will achieve the same result for your outbound by automating this verification, which is ideal if you regularly send out bulk emails and don't want to spend considerable time verifying all the addresses.

So tell me, which tool are you thinking of testing for your email address verification?