Real-time checking of e-mail addresses

Email verification allows you to ask users to correct invalid email addresses before they submit a form or order.

Endereco's email verification detects incorrectly written, invalid or undeliverable email addresses in real time as they are entered. A multi-stage verification process evaluates each email according to various criteria.

All e-mail addresses are checked for compliance with standard spelling rules.

The domain will be checked. If the domain is not correct, the e-mail address does not exist.

The likelihood of fraud is minimized because our service ensures that only valid email addresses, not fake ones, enter your system.

How does Endereco's email verification work in practice?

Real-time feedback

During the input process, the e-mail address of a user is checked. Within a few seconds we can give feedback on the entered address while the form is still being filled in, and in case of mistakes we can inform the user about a necessary correction. If all checks are passed successfully, we give "green light".

E-mail check - step by step

Every e-mail address is first checked for correct syntax. A valid e-mail address always consists of an "@", a prefix in front and the domain behind it. The Top Level Domain, which usually stands for a country or a company, is separated by a dot.

Next, we check the email for a valid Top Level Domain.

The "Top Level Domains" are administered centrally by the IANA (Internet Assigned Numbers Authority) and are constantly updated. As of July 2019 there are 1,530 valid Top Level Domains registered worldwide, some have been deleted in the meantime and are therefore invalid.

The mail server of each domain gives different feedback on the mailboxes available there, depending on the configuration.

This allows you to detect invalid email prefixes and to identify full or undeliverable mailboxes.

A comparison with different blacklists detects one-time addresses or e-mail addresses that are on SPAM lists. These are not always serious and should at least be internally marked or excluded.

The MX record of a mail server indicates under which "Fully Qualified Domain Name" the mail server for a domain or subdomain can be reached. Only if this name is valid, the e-mail can actually be delivered to the domain.

Checking the mail server

Our service tries to send a message to the mail server and processes its response. According to the replies from the mail server, it is possible to determine the validity of the e-mail address with great accuracy.

As a result of our effective e-mail address verification, you will have clean and up-to-date information about your customers!

Things to know about TOP Level Domains

Internet Top Level Domains are administered in the so-called Root Zone Database by IANA and can be distinguished according to various criteria.

  • Country code domains (e.g. "de", ".at" or ".ch") consist of 2 letters
  • internationalized TLDs (e.g. xn--fiqs8s stands for .中国 China)
  • ICANN generic TLDs (e.g. .appartments)
  • internationalized generic TLDs (for Chinese or Cyrillic scripts)
  • geographical TLDs that can be registered per country or continent. (in Germany e.g. .berlin or .amsterdam)
  • TLDs of trademarks (e.g. .axa or .bently)
  • Special forms of domains (e.g. .local or .localhost), which are used separately


There are several ways to connect the Endereco email verification system to your company. We offer you numerous ready-made solutions as plug & play modules.

Of course you can integrate our API directly into your company software or website.

Try our e-mail test live!

We have set up an OXID demo shop for you. There you can easily try out all our services.

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Here you will find information about our product world, as well as all available Plug&Play modules and API.

Robert Rieser
CEO - Contact person for your inquiries

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