The Importance of Validating Email Syntax: Challenges and Solutions

Learn about the challenges associated with email syntax validation, why it's important, and the Melissa Email solutions that can help.

Email addresses have become an essential component of modern communication, and validating syntax has become an important part of maintaining efficient and effective communication channels. However, this is no easy task. With the growing number of email providers and a constant influx of new emails, it can be difficult to correct and validate domains and mailbox names.

What is a Valid Email?

The Request for Comments (RFC) 5322, proposed by the Internet Engineering Task Force (IETF), is the general standard for email syntax.

At a high level, valid emails:

  1. Must include a local-part (mailbox name) and domain part, separated by the “@” symbol, e.g.
  2. Can have a maximum length of 254 octets (8-bit units) – for ASCII, this means 254 characters, while other UTF-8 characters may be 1-4 octets each.
  3. May contain alphanumeric characters in the domain part, as well as periods and hyphens.
  4. May contain alphanumeric characters in the local part (mailbox), including some special characters.
  5. Are case-insensitive for both the local part and domain.

These are some common rules, though there are a few other rules and exceptions to consider as well.

Challenges With Email Syntax Corrections

One of the main challenges of validating and correcting syntax for email addresses is the lack of a universal email address format. While there are common conventions for constructing email addresses, such as using the "@" symbol to separate the local part from the domain name, the rules can vary depending on the email service provider.

The RFC specifications provide a set of guidelines for how email addresses should be formatted, but they are not always strictly adhered to by email providers or users. For example, many email providers will only allow alphanumeric ASCII characters, though many special characters are considered legal. Some providers will even allow users to create email addresses with emojis; though this would be bad practice, it is not illegal and is becoming more common.

These RFC specifications have been updated many times since their initial publication in 1982, with new rules and guidelines added to reflect changes in technology and best practices. This means that email providers and users must stay up to date with the latest RFC specifications in order to ensure that their email addresses are valid and deliverable.

Moreover, some email addresses are intentionally designed to be difficult to validate. Spammers may use malformed email addresses to avoid detection by spam filters. For example, uses a hyphen in the domain name. While hyphens are allowed in the domain name, they are not typically used by major email providers. This means that validation tools must be able to detect and correct malformed email addresses without flagging legitimate ones as invalid.

Why do we need to correct them?

  • Ensuring emails reach their intended recipients: Syntax errors can cause emails to bounce, preventing them from reaching their intended recipients.
  • Maintaining sender reputation: Syntax errors can cause email servers to mark emails as spam, which can negatively impact sender reputation.
  • Saving time: Correcting syntax errors can save time by reducing the need for manual intervention and resending emails.

How can Melissa help?

Email validation tools, like Melissa's Global Email Web Service, can be an effective way to prevent the unintended consequences of syntactically erroneous emails. With Global Email Web Service, businesses can benefit from a comprehensive email validation process that includes multiple checks and live verifications to ensure that email addresses are valid.

When an email enters the service, the syntax of the email is first checked to ensure that it is properly formatted. Melissa adheres to widely accepted RFC guidelines that are observed by most email providers. In addition, we can confidently correct many invalid emails from typos. For instance, following the local part and domain name structure, an email like would be corrected to Or, as in the case mentioned previously, could be corrected to After the preliminary syntax changes occur (if there are any), the email is validated by verifying the mailbox and domain name. With every response, we return result codes indicating the actions or validations performed from the service, including any corrections made.

We are continuing to refine the process and improve our correction logic as we identify new best practices observed by major email providers. In the future, we will be expanding our correction logic, as well as fine-tuning existing logic in adherence to widely accepted industry standards.

How to Choose a Solution

Find the right address solution for your business by requesting a demonstration today.

At Melissa, we’ve leveraged 38 years of address verification expertise to give you the best possible products. Learn more from our collection of Address Experts articles.

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