What Happens During the Email Verification Process?

Verifying your email list is a simple process for the user. Download the list from your database, upload it to ZeroBounce, and we’ll handle the rest.

But what exactly happens during the email verification process?

Let’s break down each step so that you can better understand what happens to your email addresses after you upload them.

Step 1 - Syntax checkⓘ and verification

A preliminary check begins after uploading your list via the bulk upload tool or the API.

This check verifies that the email address follows the proper syntax. Proper syntax includes the correct structure (username followed by email domain) and allowed characters (certain special characters are not permitted in different parts of the email address).

It will also identify typos or misspellings and attempt to correct them until it provides a valid format.

Step 2 - DNS record check

An email domain needs to be configured with the proper DNS records (MX or A-type) to receive incoming email messages.

The second step verifies that the domain has these records, allowing us to perform a real-time SMTP checkⓘ.

Step 3 - Spam trap check

Before attempting the SMTP check, ZeroBounce scans each email address for known spam signatures associated with spam traps.

A spam trap is a tool internet and blacklist services use to identify spoofers and spammers. Different types of spam traps exist, and they typically appear to be regular email addresses. Old email addresses no longer in use are often repurposed as spam traps.

If the verifier identifies spam traps in this step, it marks them accordingly.

Step 4 - SMTP checkⓘ

An SMTP (Simple Mail Transfer Protocol) check is a test that attempts to connect to the email server and measures the response time. The test measures the email server’s health and whether or not it’s properly configured to send and receive emails.

A failed SMTP checkⓘ can indicate issues with the email server, such as improper configuration, which will cause incoming emails to bounce. Some email servers are also not configured to receive incoming mail.

Step 5 - Proprietary technology check

At this step, ZeroBounce leverages its proprietary technologies to continue testing the validity of the email address. This step allows the verifier to deliver our 99.6% accuracy guarantee and lets it identify more than 30 types of email statuses.

Step 6 - Validity check

If an email address fails any checks at this step of the email verification process, it is marked invalid. The email verifier then proceeds to the following address on your list.

Step 7 - Further qualifying your emails

Any emails that pass all prior checks will undergo further investigation. Myriad processes take place, which allow us to further qualify the email address into one of the following categories when applicable:

The verifier marks the email address with the corresponding status. These high-risk emails are unsafe and should be eliminated from your list.

Step 8 - Investigate “unknowns”

At this late stage, the verifier will know whether most of your email addresses are valid or invalid, along with the address type. However, there may still be some unknowns based on the success rate of previous checks.

The email verification process allows the email verifier to retest these “unknown” results using new IP addresses from different geographical locations. This strategy will enable it to work around specific anti-spam prevention tactics, such as greylisting.

In most cases, this process is successful and grants you the greatest percentage of known results.

Step 9 - Data append

ZeroBounce enriches your email list with key data points at the final step of the email verification process. The appended data can include the following:

The email verification process moves quickly, allowing ZeroBounce to verify 100,000 email addresses in approximately 45 minutes. Additional time may be required depending on specific SMTP configurations and anti-spam technologies.

This email verification process gives customers the most accurate results available (99.6% guaranteed). It also identifies more than 30 types of email addresses and enriches your email list with any additional social or email server data.

Related Articles

Why is email verification crucial for businesses?

What is the difference between hard and soft bounces?

Why do emails bounce in the first place?

What is a disposable email, and why is it problematic?