{"id":94188,"date":"2026-09-24T06:22:49","date_gmt":"2026-09-24T06:22:49","guid":{"rendered":"https:\/\/mailrelay.com\/?post_type=glossary&p=94188"},"modified":"2026-10-07T17:59:02","modified_gmt":"2026-10-07T17:59:02","slug":"email-service","status":"publish","type":"glossary","link":"https:\/\/mailrelay.com\/en\/glossary\/email-service\/","title":{"rendered":"Email Service"},"content":{"rendered":"\n

An email service<\/strong> is the set of servers, protocols and applications that lets you send, receive, store and organize messages over the Internet. Gmail, Outlook.com and Proton Mail are examples of email services; applications such as Outlook or Thunderbird can also work as clients for checking several accounts.<\/p>\n\n

The key difference is simple: regular email is designed for one-to-one or small-group conversations<\/strong>, while an email marketing platform is built to manage subscribers, automate campaigns, send large volumes and measure results.<\/p>\n\n

<\/p>\n\n

What is an email service?<\/h2>\n\n

An email service provides the infrastructure needed to exchange digital messages between a sender address and one or more recipient addresses.<\/p>\n\n

A message can include text, images, links and attachments. The provider takes care of receiving it, carrying it across the Internet, storing it in the right mailbox and making it available to the recipient.<\/p>\n\n

In most cases, users don’t need to run their own servers. They can access their account through a website, a mobile app or a desktop program. There are free services for personal use, business plans tied to your own domain and enterprise solutions with additional administration, security and storage.<\/p>\n\n

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Short definition:<\/strong> an email service is a digital infrastructure that lets you send, receive and manage messages using an email address.<\/p>\n<\/blockquote>\n\n

How does email work?<\/h2>\n\n

Although sending seems instant to the user, several components are involved behind the scenes:<\/p>\n\n

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  1. Writing:<\/strong> the sender writes the message in an email client or webmail and clicks \u201cSend\u201d.<\/li>\n\n\n\n
  2. Outgoing:<\/strong> the sender’s service accepts the message and uses SMTP to send it.<\/li>\n\n\n\n
  3. Locating the recipient:<\/strong> the servers query DNS to identify which system receives email for the destination domain.<\/li>\n\n\n\n
  4. Transfer:<\/strong> one or more mail servers carry the message to the receiving server.<\/li>\n\n\n\n
  5. Validation:<\/strong> the destination system checks things such as authentication, sender reputation, the presence of malware and the likelihood of spam.<\/li>\n\n\n\n
  6. Delivery:<\/strong> if the message is accepted, it is stored in the recipient’s inbox or another folder.<\/li>\n\n\n\n
  7. Reading:<\/strong> the recipient opens it in webmail or syncs it with an app using IMAP; in older setups, they can also download it using POP3.<\/li>\n<\/ol>\n\n
    \"Diagram
    The journey of an email from the sender to the recipient’s inbox.<\/figcaption><\/figure>\n\n

    A server accepting a message doesn’t guarantee that it will appear in the primary inbox. Deliverability<\/strong> depends on, among other factors, domain authentication, sender reputation, list quality and how recipients react.<\/p>\n\n

    Components of an email service<\/h2>\n\n

    Several related terms are often used as if they meant the same thing, but they don’t:<\/p>\n\n

    Element<\/th>What it is<\/th>Example<\/th><\/tr><\/thead>
    Email address<\/td>Identifier of a mailbox<\/td>\u2018name@company.com\u2019<\/td><\/tr>
    Email provider<\/td>Company that hosts accounts and mailboxes<\/td>Gmail, Outlook.com, Proton Mail<\/td><\/tr>
    Email server<\/td>System that sends, receives or stores messages<\/td>SMTP or IMAP server<\/td><\/tr>
    Webmail<\/td>Interface accessible from the browser<\/td>The Gmail website<\/td><\/tr>
    Email client<\/td>Application for checking and managing accounts<\/td>Thunderbird, Apple Mail, Outlook<\/td><\/tr>
    Protocol<\/td>Technical rules for transferring or retrieving messages<\/td>SMTP, IMAP, POP3<\/td><\/tr>
    Email marketing platform<\/td>Software for campaigns, lists, automation and metrics<\/td>Mailrelay<\/td><\/tr><\/tbody><\/table><\/figure>\n\n

    The same brand can cover more than one function. For example, Outlook can refer to both a web service and an email application. That’s why, before comparing options, it’s worth identifying whether you’re talking about hosting, an interface, a program or a sending platform.<\/p>\n\n

    SMTP, IMAP, POP3 and webmail: differences<\/h2>\n\n

    SMTP, IMAP and POP3 are not providers or account types: they are protocols that serve different purposes.<\/p>\n\n

    Technology<\/th>Main function<\/th>Where messages are kept<\/th>Recommended use<\/th><\/tr><\/thead>
    SMTP<\/strong><\/td>Sending and transferring email<\/td>Not used as a mailbox for reading messages<\/td>Outgoing messages and communication between servers<\/td><\/tr>
    IMAP<\/strong><\/td>Reading and managing the mailbox in sync<\/td>Mainly on the server<\/td>Everyday use from several devices<\/td><\/tr>
    POP3<\/strong><\/td>Downloading messages from the mailbox<\/td>Depends on the client settings; it can keep or delete the copy on the server<\/td>Local access or scenarios with limited connectivity and storage<\/td><\/tr>
    Webmail<\/strong><\/td>Accessing email from a browser<\/td>On the provider’s servers<\/td>Easy access without installing an app<\/td><\/tr><\/tbody><\/table><\/figure>\n\n

    SMTP: the sending protocol<\/h3>\n\n

    SMTP<\/strong> stands for Simple Mail Transfer Protocol<\/em>. It is used to send messages from a client to the outgoing server and to transfer email between servers. It is not designed to organize the inbox or sync folders.<\/p>\n\n

    It is the standard for transporting email on the Internet, defined in RFC 5321<\/a>.<\/p>\n\n

    IMAP: syncing across devices<\/h3>\n\n

    IMAP<\/strong> lets you read and manage messages that stay on the server. Actions taken on one device \u2014reading, moving, archiving or deleting\u2014 are reflected on the other devices connected to the same account.<\/p>\n\n

    It is usually the most practical option for people who check their email on their phone, in the browser and on their computer. The modern version of the protocol is described in RFC 9051<\/a>.<\/p>\n\n

    POP3: downloading the mailbox<\/h3>\n\n

    POP3<\/strong> was designed to retrieve messages stored on a server. Traditionally, they were downloaded to the computer and the remote copy was deleted, but today’s clients can be set up to leave it on the server.<\/p>\n\n

    It offers fewer syncing and remote management options than IMAP. It can still be useful when you want to keep a local archive or work with limited resources. Its basic specification is set out in RFC 1939<\/a>.<\/p>\n\n

    Webmail: access from the browser<\/h3>\n\n

    Webmail<\/strong> is not a protocol but a web interface. It lets you log in and check your mailbox without installing a program. Gmail, Outlook.com and Yahoo Mail offer webmail, although behind the scenes they use protocols and server systems to send, receive and store messages.<\/p>\n\n

    Types of email services<\/h2>\n\n

    Services can be classified by their purpose:<\/p>\n\n

    1. Free personal email<\/h3>\n\n

    It is aimed at personal communication and usually includes webmail, mobile apps, spam filters and a certain amount of free storage. It normally uses the provider’s domain, such as \u2018@gmail.com\u2019 or \u2018@outlook.com\u2019.<\/p>\n\n

    2. Business email with your own domain<\/h3>\n\n

    It lets you use addresses such as \u2018sales@company.com\u2019. It strengthens brand identity and usually includes centralized administration, aliases, calendars, security controls and support.<\/p>\n\n

    3. Self-managed corporate email<\/h3>\n\n

    The organization runs its own servers or a dedicated infrastructure. It provides technical control, but it requires know-how, maintenance, backups, monitoring and ongoing security and deliverability measures.<\/p>\n\n

    4. Transactional email service<\/h3>\n\n

    It sends automated messages triggered by an action or event: purchase confirmations, password resets, shipping notices or account notifications. These messages are usually integrated with a website or app via SMTP or API. You can learn more about this concept in the guide to transactional emails<\/a>.<\/p>\n\n

    5. Email marketing or bulk email platform<\/h3>\n\n

    It is designed to send newsletters, promotions and communications to a list of subscribers. It includes contact management, segmentation, unsubscribes, templates, automations, testing and analytics. It doesn’t replace your everyday work mailbox: it meets a different need.<\/p>\n\n

    Advantages of email services<\/h2>\n\n

    Email is still an essential tool for individuals and businesses for several reasons:<\/p>\n\n