Microsoft Exchange Online vs Zimbra Collaboration

Microsoft Exchange Online9.3Visit Zimbra Collaboration9.1Visit

Higher score Microsoft Exchange Online #1 in Mail Server Software 9.3/10 Paid ✓ 0 of 5 features Visit Microsoft

vs

Zimbra Collaboration #2 in Mail Server Software 9.1/10 Free plan Free plan✓ 0 of 5 features Visit Zimbra

• Microsoft Exchange Online fits best

  Microsoft-centric business email

• Zimbra Collaboration fits best

  Full-featured open-source collaboration mail

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Side by side

Feature	Microsoft Exchange Online 9.3/10 Visit ↗	Zimbra Collaboration 9.1/10 Visit ↗
At a glance
Editor score	9.3	9.1
Ranking	#1 in Mail Server Software	#2 in Mail Server Software
Best for	Microsoft-centric business email	Full-featured open-source collaboration mail
Pricing model	Paid	Free
Starting price	—	Free plan
Free plan	—	✓ (best)
Free trial	—	—
Deployment	Cloud, Browser extension	Cloud, Self-hosted, Desktop, Mobile
Platforms	Web, Windows, macOS, iOS, Android	Web, Windows, macOS, Linux, iOS, Android
Support	Phone, Docs · 24/7	Email, Phone, Tickets, Community, Docs · 24/7
Integrations	2 integrations	5 integrations
Built for	Small business, Mid-market, Enterprise	Small business, Mid-market, Enterprise
Features Microsoft Exchange Online 0/5 · Zimbra Collaboration 0/5
Webmail interface	Not checked yet	Not checked yet
IMAP/POP3 access	Not checked yet	Not checked yet
Mobile sync	Not checked yet	Not checked yet
Antispam tools	Not checked yet	Not checked yet
High availability	Not checked yet	Not checked yet
Specs
License model	Not checked yet	Not checked yet
Mailbox limit	Not checked yet	Not checked yet
Our review
Pros	Outlook access across web, desktop, and mobile platforms Spam filtering, archiving, DLP, and compliance features Migration support for Exchange, IMAP, PST, and other systems	Combines email, calendars, contacts, tasks, and file sharing Supports IMAP, POP, SMTP, CalDAV, CardDAV, and ActiveSync Includes migration, security, backup, and restore capabilities
Cons	Paid access is required for every mailbox Plan 1 limits primary mailbox storage to 50 GB Some archive capabilities depend on licensing and admin enablement	Commercial licensing uses quote-based pricing Hosted storage and attachment limits depend on the hosting provider Its broad feature set may exceed basic email-only requirements
Our verdict	Microsoft Exchange Online is a cloud-hosted business email and calendaring service for organizations that want custom-domain mailboxes alongside Outlook access. It supports email, calendars, contacts, shared mailboxes, browser access,… Read the review →	Zimbra Collaboration is an open-source email and collaboration suite from Synacor for businesses, educational institutions, service providers, and organizations that need control over deployment and data. It combines email, contacts,… Read the review →

Strengths and trade-offs

• Microsoft Exchange Online — where it wins

  • Outlook access across web, desktop, and mobile platforms
  • Spam filtering, archiving, DLP, and compliance features
  • Migration support for Exchange, IMAP, PST, and other systems

  Where it doesn't

  • Paid access is required for every mailbox
  • Plan 1 limits primary mailbox storage to 50 GB
  • Some archive capabilities depend on licensing and admin enablement

• Zimbra Collaboration — where it wins

  • Combines email, calendars, contacts, tasks, and file sharing
  • Supports IMAP, POP, SMTP, CalDAV, CardDAV, and ActiveSync
  • Includes migration, security, backup, and restore capabilities

  Where it doesn't

  • Commercial licensing uses quote-based pricing
  • Hosted storage and attachment limits depend on the hosting provider
  • Its broad feature set may exceed basic email-only requirements

• Microsoft Exchange Online9.3/10 · Paid

  A Microsoft-centric hosted mailbox service with Outlook, archiving, compliance, and migration tools.

  Visit MicrosoftFull verdict →
• Zimbra Collaboration9.1/10 · Free plan

  A broad open-source suite for organizations that need email, collaboration, and deployment control.

  Visit ZimbraFull verdict →