Kolab review
A broad open-source mail and collaboration suite for teams managing their own infrastructure.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Kolab is an open-source communication and collaboration suite for organizations, families, and teams that want to operate their own email and groupware infrastructure. Its scope extends beyond webmail: users can work with calendars, tasks, contacts, file storage, video conferencing, and collaborative document editing. Access is available through the web, self-hosted deployments, Linux, iOS, and Android, with standards-based support for IMAP, SMTP, ActiveSync, CalDAV, and CardDAV. It is best suited to buyers who want control over their mail environment and need shared productivity features alongside email.
The platform’s main strength is its breadth of collaboration features and client compatibility. Shared folders and calendars support group work, while user aliases, signatures, spam filtering, virus scanning, and support for DKIM, DMARC, and SPF address common mail-management needs. Kolab also integrates with Thunderbird, Outlook, eM Client, Apple Mail, and Apple Calendar. That combination gives organizations several ways to connect existing desktop and mobile workflows rather than relying only on the webmail client.
Kolab’s open-source, free model fits teams prepared to manage their own deployment, configuration, and ongoing infrastructure. The self-hosted approach offers a better fit for organizations that prioritize operational control over a managed service experience. Mobile coverage is available through third-party apps, and buyers should account for that when planning user access. Choose Kolab when a single system for standards-based email, groupware, and collaboration is more important than turnkey hosting. Buyers seeking a provider-managed mail service or first-party mobile applications should consider a different type of product.
Kolab pros and cons
- Where it wins
- Combines email, calendars, tasks, contacts, and shared resources
- Supports IMAP, SMTP, ActiveSync, CalDAV, and CardDAV
- Includes spam filtering, virus scanning, and email authentication support
- Where it doesn't
- Self-hosted deployment requires your own infrastructure
- Mobile access relies on third-party apps
- Not suited to buyers seeking a managed hosted mail plan
Kolab fact sheet, pricing and score →
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