Best Self-Hosted Alternatives to Microsoft 365
Microsoft 365 costs about $84/year and keeps your data on its servers. These researched, open-source alternatives give you the same workflow on hardware you own — here's what each needs to run.
The alternatives
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Head-to-head
The complete admin-UI suite vs. the bare config-file container.
The full groupware suite vs. the lighter wizard-built mail stack.
One Rust binary vs. the full container suite.
Common questions
Are these Microsoft 365 alternatives really free?
The software is open-source and free to run. Your only cost is the server it runs on — often a few dollars a month, less than most SaaS subscriptions.
How much server do I need to self-host one?
Most of these run comfortably on a small VPS — 1–2 GB of RAM is enough for a single-user or small-team setup. Each app's page lists its minimum RAM.
Will I lose features by leaving Microsoft 365?
It depends on the app. The alternatives below cover the core workflow; polish and integrations vary, so check each one's stack and difficulty before you commit.