An email address is a unique identifier of your email account used for sending and receiving digital messages. The message exchange happens through platforms created and maintained by inbox providers, which store email addresses and manage email communications.
What does an email address consist of?
To ensure successful communication, an email address has to be valid and functional. It needs to contain 3 distinct sections:
- Local part or user name
- The @ symbol
- Domain name
The user name comes before the @ symbol, while the domain name follows it—this structure was standardized by the Request for Comments publication issued by the Internet Engineering Task Force (IETF).
User name
The user name, or the local part, is the name someone chooses when creating an email address. While customizable, the user name still has to follow the technical standards issued by the IETF.
The user name can contain any of the following characters:
- The uppercase and lowercase alphabet letters
- Digits from 0 to 9
- Special characters like !#$%&’*+-/=?^_`{|}~
- Periods
Your user name can’t begin or end with special characters or periods or use these consecutively. Here are some examples of valid and invalid user names:
| Invalid user name | Valid user name |
| johnsmith..87@ | johnsmith.87@ |
| #johnsmith@ | john#smith@ |
| johnsmith$@ | john$smith@ |
Domain name
The domain name refers to the email server that handles receiving and sending messages for the email address. Alternatively, it can reflect a company name if the business that owns the address registers a custom domain name for its employees.
This section of the email address typically consists of 2 components, separated by a dot:
- Second-level domain (SLD)
- Top-level domain (TLD)
SLDs are the part of the domain name you see before the dot and the TLD component. They contain the name of the service or organization that holds the domain. Some well-known domains are easily recognizable, like “gmail.”
The TLDs are the last section of the qualified domains and signify their intended use, such as:
- .com for commercial use
- .org for organizations
- .net for networks
- .edu for educational institutions
- .gov for government agencies
A valid domain name follows predetermined requirements. It can consist of alphabet letters, numbers, and hyphens, and it can’t begin or end with a hyphen.
| Invalid domain name | Valid domain name |
| johnsmith@companyname-.com | johnsmith@company-name.com |
| johnsmith@companyname#1.com | johnsmith@companyname.com |
| johnsmith@companyname | johnsmith@organizationname1.org |
Common uses for email addresses
Email addresses have various use cases, such as:
- Personal communication: Individuals use email addresses for personal purposes, like private communications and creating accounts on various platforms.
- Professional use: Businesses often create dedicated email addresses for their employees to enable easier professional communication and make their brands easily identifiable based on the custom domain names.
- Email marketing: Many businesses collect email addresses of potential or existing customers as part of their email marketing strategy. Building email lists enables them to send personalized, properly timed emails to pull in new prospects, keep their current customers interested, and promote their products and services.
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