Email verification is an email hygiene task that’s essential before you begin sending emails externally. But if you’re just getting started using an email checker, you probably have a lot of questions like:
- Where do I start?
- Do I just discard all addresses that aren’t verified as valid?
- Why is verification so important?
The process can be a little intimidating.
In this article, we’ll walk through five email verification best practices designed to reduce bounce rates and improve deliverability. We’ll also cover how to avoid verification-related issues and how to save time and money using email verifiers.
Why email verification is so important for cold outreach
Email verification is the key to keeping bounce rates low and protecting your domain.
Without it, you’re likely to end up with at least some bounced emails on your contact list. Bounces damage sender reputation, which affects the deliverability of your emails domain-wide.
This doesn’t just impact email deliverability for your outreach campaigns. It can also negatively affect the emails you send to your users, customers, and partners, causing them to start bouncing or landing in spam.
This can quickly turn into a nightmare scenario.
No one wants to be the SDR whose outreach campaign tanks the sender reputation for the company domain—preventing marketing from sending product updates, sales from sending follow-ups, customer success from sending onboarding emails, and executives from sending fundraising messages.
For more, read our article on who benefits most from email verification.
Five essential email verification best practices
Create a successful email verification workflow with these best practices for when to do it, red flags to watch for, and tools to use.
1. Verify all new contacts
The first rule of email verification is: Never take email addresses at face value—especially if you plan to use them in an outbound campaign.
Email addresses can come from a range of sources. For example, you might have collected them from a B2B database, via a social media platform like LinkedIn, during an industry event, or from an online form.
Whether you rely on first- or third-party data to build contact lists, email addresses can be outdated, risky, or flat out incorrect. So instead of assuming your contact list is valid, take time to verify every new email address you collect.
Here’s a simple rule of thumb. Verify any email address that:
- Is from outside your organization
- You’re planning to send emails to
- You’re going to initiate contact with (i.e., you’re not replying to their message)
Follow this best practice whether you’re using your primary business email address or a separate email domain that you set up for outreach purposes.
If you don’t verify new contacts, chances are you’ll end up with at least some unsafe email addresses on your list.
For example, some might be spam traps or honeypots—fake email addresses designed to catch and block spammers. Or some might be personal email addresses, which can lead to legal consequences if you use them for business purposes.
2. Reverify old contacts before reengaging
Planning to revisit an old contact list without reverifying the email addresses? Not so fast. Email data becomes outdated quickly—in as little as a month.
In fact, a recent Hunter study found that 2.3% of a sample contact list was outdated after just eight weeks.
There are tons of reasons emails can become invalid, including when recipients change jobs or switch to a different inbox. Expired domains and server or DNS configuration updates can also make email addresses invalid.
In some cases, the contact you initially added to your list might have been a temporary disposable email address. This can happen when someone wants access to a gated resource but doesn’t want to provide their actual email address. While the email address might have been valid at first, it would bounce if you used it weeks or months later.
Because email addresses become out of date so quickly, it’s important to reverify old contacts before you reengage them with a new email campaign. This way, you take steps to avoid exceeding the recommended 2% bounce rate threshold.
This is particularly important when reaching out to leads who were qualified but went inactive due to timing issues or budget concerns. Job changes can invalidate old leads’ contact information, making email verification critical.
3. Treat accept-all status with extra care
Accept-all domains are especially tricky for cold outreach. Also known as catch-all addresses, they’re set up so they don’t reject any emails—even if you send them to mailboxes that don’t exist on the domain.
But that doesn’t mean these domains won’t bounce back any emails. In fact, Hunter’s tests found that accept-all addresses are 27 times more likely to bounce than standard email addresses.
Here’s why this high bounce rate happens:
When an email address has an accept-all server configuration, it can’t be verified as either valid (which means it actually exists) or invalid (which means it doesn’t exist) using most email verification methods. This means sending emails to these addresses can be a roll of the dice.
So, what’s the solution?
Hunter’s Email Verifier can verify accept-all addresses with several major email providers, using proprietary technology. But some domains will still trigger an “accept all” email status, like this:
You don’t necessarily have to stop emailing accept-all domains, but using catch-all email addresses without additional checks can compromise your sender reputation. See Hunter’s guide to accept-all email addresses for detailed guidance.
4. Choose an email verifier that’s right for you
Technically, you could verify an email address with a quick test email. But this method would lead to unnecessary bounces and wouldn’t be possible to scale for a large list.
For reliability, accuracy, and speed, you need an email checker—but not all are created equal. Many of the most popular tools claim 99% accuracy, yet few actually meet that threshold.
If you need to send a lot of cold emails, that discrepancy can get expensive. After all, using tools that don’t live up to the hype and provide inaccurate information can cost you your sender reputation.
To check these claims and benchmark these tools, Hunter tested eight of the most popular email verifiers. During the test, each tool attempted to verify the same 3,000 email addresses—2,700 real addresses and 300 invalid ones divided across small and medium-sized businesses (SMB), mid-market, and enterprise segments.
The result?
Hunter’s email checker came out ahead with the best overall accuracy across segments. For the SMB and mid-market datasets in particular, Hunter maintained a lead of nearly 10 percentage points, making it by far the most reliable email verifier on the market.
So, is Hunter the right choice for everyone looking to verify email addresses? The Email Verifier is certainly a smart choice when accuracy is your top priority.
But you should also consider the tool’s other features. Hunter is a complete platform for email outreach. In addition to the Email Verifier, Hunter has tools like:
- Email Finder, which locates the verified email address for any professional
- Domain Search, which finds email addresses from any company name or website
- Discover, which fuels your B2B prospecting workflow
- Campaigns, which manages your cold outreach sends and replies
- Signals, which finds your next best customer using intent data
- AI Writing Assistant, which generates high-converting, personalized emails
If you’re looking for a fully featured platform that offers superior email verification accuracy and that can handle every aspect of your outreach, Hunter should be at the top of your list.
If you just need a quick and easy way to verify a few email addresses, another tool might check those boxes without adding any extra features. And if you’re not sure, you can always test out Hunter’s Email Verifier at no cost.
5. Verify email addresses where you need it
Email verification isn’t an optional step for cold outreach. It’s basic email hygiene that should become a habit. But the habit won’t stick unless you make it easy to do within your outreach workflow.
If your tech stack is relatively simple and you’re just getting started with cold outreach, using a standalone email checker might be perfectly fine. But if you need to work in your existing tools, you need a different solution.
The good news?
You can verify email addresses in virtually any tool—as long as your email verifier has a reliable API. For example, with Hunter API, you can:
- Set up real-time verification in your online forms. This way, every contact marketing passes along to sales is verified before sending a single follow-up email.
- Verify contacts in your CRM without opening another tool. This way, you can check old contacts and pick up where you left off with paused deals.
- Use bulk verification for new contact lists. This way, you can quickly verify new lists from events or B2B databases—and still get accurate data.
With an API, email verification doesn’t have to be strictly a sales or marketing tool. Everyone can use it as part of their workflow, working together to keep bounce rates low and email deliverability high.
Wrap up
Email verification should be an essential part of your process whenever you send an external email. Without it, you’re likely to run into deliverability problems and sender reputation issues.
While email verification can be complex, you can simplify the process and improve your results by following best practices and using a reliable email checker.
