SMART Migration is a powerful enterprise migration platform, but it is important to be clear about what it is not designed to do.
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It is not a real-time sync tool
While incremental migration is supported, SMART Migration is not a continuous background sync service. Scanning thousands of OneDrive accounts and site collections for changes on a frequent basis carries a significant time cost and is not practical at scale. Microsoft also does not support pushing real-time file change notifications to external systems — the basic webhook mechanism that exists in SharePoint lacks the granularity and reliability needed for this purpose.
It is not a sync engine between Microsoft 365 and Nextcloud
This is not a limitation of SMART Migration specifically, but a fundamental reality of the two platforms. Microsoft 365 and Nextcloud are architecturally incompatible at almost every level: their file models, metadata structures, versioning systems, permission models, and APIs share no common ground. True bidirectional sync between the two systems is not a viable option for any tool. The goal of SMART Migration is a clean, governed, one-way migration from Microsoft 365 to Nextcloud — not an indefinite bridge between two incompatible worlds.
It is not a cloud service
SMART Migration runs entirely on your own infrastructure. No data passes through external cloud services, and there are no hidden per-file or per-GB charges.
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Reverse Migration – Back to SharePoint
Although SMART Migration is designed as a one-way migration from Microsoft 365 to Nextcloud, full reverse migration back to SharePoint is supported — made possible by a unique feature of SMART Migration: the proxy link.
What is the proxy link?
When a file is migrated from SharePoint to Nextcloud, SMART Migration does not simply delete the original file from SharePoint. Instead, it converts the source file into a lightweight .url file — a proxy — that points to the file’s new home in Nextcloud.
This is where things get remarkable.
From the end user’s perspective, absolutely nothing changes. The file still appears in exactly the same place in SharePoint, in the same library, in the same folder, with the same name. When the user clicks it, they are seamlessly redirected to the file in Nextcloud — opened directly, without friction, without confusion, and without any need to know or care that the file has moved. For the user, it just works.
Immediate and significant storage savings
While the user experience remains unchanged, the impact on SharePoint storage is immediate and dramatic. The original file — along with its entire version history, which can represent many times the size of the current file — is replaced by a tiny .url text file that is just a few bytes in size. The storage footprint in SharePoint drops to effectively zero the moment the migration completes.
This matters enormously from a cost perspective. SharePoint Online storage is expensive — typically around $2,400 USD per terabyte per year. For organisations with hundreds of thousands of files and deep version histories, the accumulated storage cost is substantial. With the proxy approach, that cost begins dropping from day one of the migration, even before the migration is complete. Files that have been migrated stop consuming SharePoint storage immediately, while files not yet migrated continue to be accessible exactly as before.
This means the migration pays for itself progressively — every file migrated is a file no longer costing money to store in SharePoint.
Gradual migration with zero disruption
Because the proxy keeps every migrated file visible and accessible in SharePoint throughout the migration, there is no “big bang” cutover moment where users suddenly find their files have disappeared. Migration can proceed gradually over weeks, months, or even years, with users continuing to work entirely normally throughout. Files in SharePoint are either the real file (not yet migrated) or a proxy pointing to Nextcloud (already migrated) — and users cannot tell the difference.
This also eliminates the risk of dual editing. Since the proxy replaces the original file in SharePoint the moment migration completes, there is only ever one place where the file lives and can be edited. There is no window during which someone could modify the file in SharePoint while someone else modifies it in Nextcloud.
Why the proxy enables full reverse migration
The proxy is not just a pointer — it is the key to full reverse migration. When SMART Migration creates the proxy, it also preserves the complete SharePoint document library metadata for every version of the migrated file. This means the original SharePoint item structure remains fully intact, including version history, metadata columns, and all item properties.
Should a reverse migration be required, SMART Migration can use this preserved metadata to re-inject the binary content of each file version back into the original SharePoint item — restoring it with complete fidelity. Nothing is lost.
Files created or modified in Nextcloud after the initial migration can also be restored to SharePoint, though these will carry only the limited metadata that Nextcloud stores, since the richer SharePoint metadata was never created for those files in the first place.
Controlled coexistence — not sync
The proxy concept does not create a sync relationship between SharePoint and Nextcloud. What it provides instead is controlled coexistence: files live in Nextcloud, users can reach them from SharePoint, and the option to fully reverse migrate back remains open for as long as needed. This makes SMART Migration’s approach fundamentally different from a simple “lift and shift” — it is a governed transition with a safety net.