Multi-tenant Microsoft 365 backup for MSPs and IT service providers
By Lucas Flores, IT Systeme Flores UG. Last updated
Restow's Service Provider edition runs Microsoft 365 backup for any number of customer tenants from one installation that you host yourself, for a one-time €1,950 (list price) and an optional update year at €595 net after the first 12 months of updates, with no fee per mailbox or tenant. Each customer gets its own tenant with delegated administrators who see only their own data, and you watch every tenant in one provider overview. In the scenario with 1,000 mailboxes across 20 tenants, the all-in cost is about €0.62 per mailbox and month (as of October 2026); at an example price of €3.00 that leaves a margin of about €2,376 a month. That is a model, not a promise.
What does the Service Provider edition include?
Everything in Community and Business, plus several tenants, delegated tenant administrators, a provider overview across all tenants and a cross-tenant API key. The table reads each capability and its status from the same product facts as the pricing page.
| Capability | Included in | Status |
|---|---|---|
| Multiple tenants and the cross-tenant REST API | Service Provider | Available, since 0.1.0 |
| Delegated tenant administrators (a customer's own administrators, limited to their tenant) | Service Provider | Available, since 0.1.0 |
| Provider overview across all tenants (status per tenant, alerts) | Service Provider | Available, since 0.1.0 |
| Several administrators with roles (members); limiting a member to chosen tenants is Service Provider | Every edition | Available, since 0.3.1 |
| REST API | Every edition | Available, since 0.1.0 |
| Alerts by e-mail, in-app, webhook and chat message (Discord, Slack, Microsoft Teams) for failed backups, failed restore checks, overdue backups and storage damage | Every edition | Available, since 0.1.0 |
| Scheduled reports (daily, weekly or monthly summary by e-mail) | Business and Service Provider | Available, since 0.1.0 |
| Audit log viewer (search, filters, details, hash-chain verification) | Business and Service Provider | Available, since 0.1.0 |
| Audit log export (CSV, JSON with hashes) | Business and Service Provider | Available, since 0.3.1 |
| Your own organization as an internal tenant, created by setup | Service Provider | Available, since 0.2.0 |
| White label | Service Provider | Planned |
Details: multi-tenancy for service providers, multi-tenancy in the documentation, Roadmap.
How do delegated tenant administrators work?
Each tenant has its own administrators who see and manage only that tenant. Tenant administrators and users can be invited in every edition; what Community and Business lack is a second tenant to delegate. Your own technicians are members of the provider team, with roles, and in the Service Provider edition a member can be limited to chosen tenants. Owners invite and change members, and every change is audited.
How do I see all my customers at once?
The provider view of the Overview lists every tenant with its status and the alerts that follow from it, and the tenant switcher finds a tenant by name or customer number. Recovery readiness shows per tenant whether a backup has been proven restorable, and alert rules can send an e-mail or a signed webhook into your ticket system when a check fails. Since 0.4.7 the owner of the installation can also enter a monthly price per mailbox and per GB or TB of stored backups under Installation › Prices, and each tenant's overview shows provider admins a card "Price per month" with what the tenant comes to at these prices. It is an estimate for you: Restow bills nothing and limits nothing, and tenant users never see the prices. How restorability is proven.
Can I connect Restow to my RMM or PSA?
Yes, through the REST API. It is documented with OpenAPI and uses keys and scopes per tenant; the Service Provider edition adds a cross-tenant key. Through it your tools can read backup, restore and verification status, jobs and storage per tenant, and a clean mailbox directory for ticketing and billing. Integration API in the documentation.
Is there white label?
Not yet. White label is planned and is not built. The roadmap shows its status.
What does it cost, and what is left per mailbox?
The Service Provider license is €1,950 once, net (pre-sale price €1,560 until general release). Pre-sale licenses include every 1.x update; from version 1.0, a license includes 12 months of updates, then an optional update year (Business €295, Service Provider €595 net per year). For the scenario with 1,000 mailboxes over 20 tenants, the cost model uses the list price plus the 4 update years that 5 years need, adds a rented VM, object storage and admin time at €80 an hour, and spreads it all over 60 months. Per mailbox and month that is €0.03 for the license, €0.04 for the update years, €0.03 for the VM, €0.04 for storage and €0.48 for admin time, €0.62 in all.
- Example monthly revenue
- €3,000
- €3.00 per mailbox and month
- Your all-in cost per month
- €624
- Example monthly margin
- €2,376
€3.00 per mailbox and month is only an example price, not a recommendation or a guarantee of what the market bears. Your actual price, cost and margin depend on your infrastructure, your support load and your market. The same example, with the cost chart and a calculator, is on the compare page; the per-mailbox figures for smaller setups are on what Microsoft 365 backup costs per user.
What came with 0.4.0 for providers?
- SharePoint Online sites are protected objects next to mailboxes and OneDrives: every directory sync finds a customer's sites, and protection rules cover all sites or selected ones. It needs one added permission and a new admin consent per customer tenant, and it is new: so far tested against a simulated Microsoft Graph.
- "All tenants" in Jobs (Service Provider only): the Jobs of Mail & SaaS and of Servers & clients list every tenant with its jobs per kind, what runs and waits, how the newest backups ended and the next run; a row opens that tenant's jobs read-only.
- File shares (SMB and NFS) are backed up without an agent on the file server, with their own jobs, restore and budgets. A customer's administrators manage the shares of their own tenant; a share in a private network needs a provider admin's approval or an installation setting.
- Ransomware detection judges every new restore point of every tenant and notifies on a suspicious one; while a finding is open, retention keeps the older restore points. The provider owner sets the thresholds and the hold. It is a tripwire, not a virus scanner. Ransomware detection.
- A notification matrix sets per event which channel gets it: the bell, each webhook and each recipient, with quick choices such as "Errors only". Installation events such as a pending update or low disk space are rows for provider admins only.
- Immutable backups work per repository. To make a customer's backups immutable, give that tenant a repository of its own: the installation's default repository cannot be made immutable. Lowering the protection needs the provider owner with a recent sign-in. Immutable backups.
What do I run, and what do my customers need to do?
You run one Docker Compose stack on a Linux server or VM, on other hardware than the systems it protects, with storage you choose: local disk, S3-compatible object storage or NFS, in the region you pick. A customer's Microsoft 365 tenant connects through a consent invitation of the shared backup app or through a Graph app that the customer creates in their own tenant. Servers and clients join through the Restow agent for Linux and macOS, and Proxmox VE hosts as a preview. Restow itself offers no hosted service.
What does Restow not do for providers yet?
- Teams chats are not backed up. SharePoint Online sites are backed up since 0.4.0, without attachments of list items, site design, navigation and workflows. Of a Microsoft 365 group, the calendar and the conversations are backed up since 0.4.5 (opt-in).
- White label is planned, not built.
- Sign-in with Microsoft and single sign-on are planned, not built.
- Immutable backups are off until turned on per repository, the installation's default repository cannot be made immutable, and they have so far been tested against a simulated S3 service only.
- Proxmox VE is a preview in every edition and not yet recommended as the only backup.
- A license includes no support, setup, operation or SLA.
Frequently asked
Can one Restow installation back up several customers?
Yes, with the Service Provider edition: any number of tenants in one installation, each tenant being one of your own customers. Restow does not count tenants or mailboxes; you use the license within what you bought. Business is licensed for one organization only.
Is each customer's data kept apart from the others?
Yes. Every tenant is its own organization with its own encryption key, and on shared storage tenants stay separated by their own prefix and key. A customer's delegated administrators see and manage only their own tenant. The multi-tenancy feature page describes the isolation at the database level.
Can I limit a technician to certain customers?
Yes. Provider team members have roles (owner, administrator, technician or read only), and limiting a member to chosen tenants is part of the Service Provider edition. Owners invite and change members, and every change is audited.
Which RMM or PSA does Restow work with?
Restow has an OpenAPI-documented REST API with per-tenant keys and scopes and, in the Service Provider edition, a cross-tenant key. Your RMM, PSA or ticketing system can read backup, restore and verification status through it. This site names no ready-made connector for a specific product; the integration is the documented API.
Can I put my own branding on Restow?
Not yet. White label is planned and not built; the roadmap shows its status. Restow itself offers no hosted service: you install and run it.
Does the license include support or operation?
No. A license includes the software; support, setup, operation and SLAs are not included and need a separate contract. Pre-sale licenses include every 1.x update; from version 1.0, a license includes 12 months of updates, then an optional update year (Business €295, Service Provider €595 net per year). If development ever stops, twelve months' notice is given and the Business and Service Provider modules are published as open source under Apache 2.0.
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