How does email verification work?

When verifying an email, there are a number of methods that we use. Some are performed as a precursor to any physical checking - we call this "pre-validation".

At a high level, and without giving away any of our trade secrets, we pre-validate by:

• Verifying a correct syntax of the email address
• Checking the domain name exists and has valid mail delivery DNS records
• Querying if the domain is configured as "accept all" - does it accept any email address
• Determining deliverability based on previous results

Once this process has completed we may also then perform a physical verification.

We do this using a number of methods, but primarily we communicate with the target mail server of the domain to see if it accepts mail for the email address being verified.

We don't actually send any mail during this process.

There are some additional processes and checks that we perform under the covers that are all related to data integrity and ensuring that we are able to deliver the best quality of results as possible.