Out of Microsoft – completely and permanently
This stack fully replaces Microsoft 365, Azure AD, Windows and all other proprietary products with open-source alternatives – hosted in Germany, controlled by you.
Collaboration & Cloud
| Microsoft Product | Open-Source Alternative | Function |
|---|---|---|
| OneDrive / SharePoint | Nextcloud Files | File sync, sharing, versioning |
| Office Online | ONLYOFFICE Docs | Browser-based editing – full MS compatibility, directly in Nextcloud |
| Microsoft Teams (Meetings) | Nextcloud Talk | Video, chat, screen sharing – directly in the browser |
| Microsoft Forms | Nextcloud Forms | Surveys and forms |
Nextcloud runs on a dedicated Hetzner server (from ~€16/month for 20 users) and is subject exclusively to German law.
Communication & Messaging
| Microsoft Product | Open-Source Alternative | Special Feature |
|---|---|---|
| Microsoft Teams (Chat) | Element / Matrix | Federated, E2E-encrypted, no vendor lock-in |
| Outlook | Thunderbird | Full-featured desktop mail client, OpenPGP integration |
| Exchange Online | Mailbox.org | Privacy-compliant email service, hosted in Germany, GDPR-compliant |
Matrix/Element is used by the European Commission (32,000 employees), the German Bundeswehr and over 40 German universities.
Desktop & Operating System
| Microsoft Product | Open-Source Alternative | Note |
|---|---|---|
| Windows 10/11 | Ubuntu LTS | Stable everyday use, long support cycles |
| Windows (Desktop) | KDE Plasma | Familiar interface for Windows switchers |
| Microsoft Office | ONLYOFFICE | Writer, Calc, Impress – full compatibility with DOCX/XLSX, familiar interface |
The migration from Windows to Linux generally goes smoothly for standard workstations. For industry-specific software we check compatibility in advance.
Mobile & Smartphones
| Product / Service | Open-Source Alternative | Description |
|---|---|---|
| Android (Google) | GrapheneOS | Hardened, de-googled Android – for Pixel devices, ideal for business use |
| Exchange ActiveSync | Nextcloud Mobile | Calendar, contacts and files via DAVx⁵ |
For most SMB employees, GrapheneOS with the Nextcloud calendar is fully sufficient.
IT Infrastructure
| Microsoft Product | Open-Source Alternative | Use Case |
|---|---|---|
| Hyper-V / Azure VM | Proxmox VE | Virtualization platform for own servers |
| Azure Active Directory | Keycloak | Identity & Access Management, SSO, LDAP |
| VPN (Azure) | WireGuard | Modern, lightweight VPN protocol |
| Windows Defender Firewall | OPNsense | Open-source firewall and router |
Proxmox is the most widely used open-source virtualization platform in Europe and forms the foundation of our infrastructure migrations.
Business & ERP
| Microsoft Product | Open-Source Alternative | Function |
|---|---|---|
| Dynamics 365 | Odoo Community | CRM, accounting, warehouse, HR in one system |
| SharePoint (Documents) | Paperless-ngx | Document management with OCR and tagging |
Odoo is modular – you start with CRM and invoicing and expand step by step.
Security & Backup
| Microsoft Product | Open-Source Alternative | Function |
|---|---|---|
| 1Password / LastPass | Vaultwarden | Self-hosted password manager (Bitwarden-compatible) |
| Azure Backup | Restic + BorgBackup | Encrypted, deduplicated backups |
| Microsoft Defender | CrowdSec | Collective threat detection and IP reputation |
Vaultwarden runs on any small server and fully replaces expensive password manager subscriptions.
Migration Roadmap
| Phase | Duration | Focus |
|---|---|---|
| 1. Analysis | 1–4 weeks | Inventory, risk assessment, scheduling |
| 2. Infrastructure | 1–3 weeks | Set up Proxmox, Keycloak, Mailbox.org |
| 3. Collaboration | 2–4 weeks | Nextcloud, Matrix/Element, ONLYOFFICE |
| 4. Workstations | 2–6 weeks | Linux, ONLYOFFICE, training |
| 5. Completion | 1–2 weeks | Stabilization, cancel Microsoft licenses |
The full process is described in our Migration Roadmap →.
Cost Comparison
A typical SMB with 20 employees pays for Microsoft 365 Business Premium approx. €280/month (as of 2025). The comparable open-source stack costs:
- Hetzner server (2× CX21): ~€12/month
- Hetzner storage: ~€9/month
- Backup: ~€2/month
- Total running costs: ~€23/month
The one-time migration costs typically pay for themselves within 6–12 months.