Exchange Online is Microsoft's cloud-hosted email server, providing business email, calendars and contacts as part of Microsoft 365. It is the underlying service behind every Microsoft 365 mailbox, whether accessed through Outlook, a mobile app or a web browser, replacing the on-premises Exchange servers that many businesses previously had to maintain themselves.
How Exchange Online works
Each user in a Microsoft 365 tenant has a mailbox hosted on Exchange Online, with email, calendar and contacts stored centrally in Microsoft's cloud rather than on a local server. Microsoft handles the infrastructure, security patching and backup of the underlying servers, while administrators manage mailbox settings, distribution lists and mail flow rules through the Microsoft 365 admin centre. Built-in protection filters spam and known malware before it reaches a user's inbox.
How UK businesses use Exchange Online
- A business migrates from an ageing on-premises email server to Exchange Online, removing the cost and risk of maintaining physical mail server infrastructure.
- An IT administrator sets up shared mailboxes in Exchange Online for departments such as accounts or support, giving multiple staff access to a common inbox.
- A company configures mail flow rules in Exchange Online to automatically flag or block emails from known suspicious domains.
- A growing business adds Microsoft Defender for Office 365 on top of standard Exchange Online Protection for stronger defence against phishing attempts.
How Advantage manages Exchange Online
Advantage manages Exchange Online configuration, security and migration from legacy email systems as part of Microsoft 365 deployments, and layers additional email security where a business faces a higher level of targeted phishing risk.
Frequently asked questions
Is Exchange Online the same as Outlook?
No. Outlook is the email application people use to read and send messages. Exchange Online is the underlying cloud email server that stores mailboxes, calendars and contacts, and which Outlook, the Outlook mobile app and webmail all connect to.
Can Exchange Online mailboxes be accessed from any device?
Yes. Because Exchange Online is cloud-hosted, mailboxes can be accessed from Outlook on a desktop, the Outlook mobile app, other email clients, or directly through a web browser, with consistent access to mail, calendar and contacts across all of them.
Does Exchange Online include spam and malware filtering?
Yes. Exchange Online includes built-in spam and malware filtering through Exchange Online Protection. Many businesses add Microsoft Defender for Office 365 on top for more advanced protection against phishing and targeted email-based attacks.
