A sensitivity label travels with a customer record from SharePoint to Outlook. It does not travel with that same record into a Postgres replica, out through a nightly analytics job, and into an S3 bucket you provisioned last quarter. Purview governed the document. The data left as a row, and the label stayed behind.
That gap is the whole comparison. Purview classifies and governs data inside the Microsoft estate. Hilt watches data movement across every layer at runtime and ties each move to the identity and the job behind it. One labels what you have. The other catches the pattern when it leaves. You will most likely run both.
What Purview does well
Purview classifies and labels data at rest. It applies sensitivity labels across Office documents, SharePoint, OneDrive, Exchange, and Teams. It enforces data loss prevention policy inside those surfaces, so a labeled document cannot be emailed externally or copied to an unmanaged location. It keeps a data catalog and lineage map across the Microsoft estate, Fabric, Azure storage, and connected sources. It runs insider risk management, eDiscovery, retention, and compliance reporting against the frameworks Microsoft customers answer to.
Standardize on M365 and Azure, ask "what do we hold, how is it labeled, and is it leaving through Outlook or SharePoint," and Purview answers that. It knows the suite. It covers the application-layer exit paths Microsoft controls. Hilt does none of this and does not try to.
Where the coverage thins
Every suite-native tool sees the surfaces it owns and stops there. That is the structural limit, not a configuration mistake.
Purview governs movement where Microsoft sits in the path. The label rides with the document inside the suite. DLP fires when a move crosses a boundary Microsoft can observe. That footprint is large and valuable. It is also bounded, and your most valuable data spends most of its life outside it.
That data moves through a production workload reading a database. Through a service account pushing to object storage. Through an AI agent pulling context out of a system of record. Through an approved pipe between two clouds. None of it runs through M365, so none of it carries a label, and none of it crosses a boundary Microsoft can watch.
Now go inside the surfaces Purview governs best, where a deeper limit holds. DLP asks one question: is this move permitted. It checks the action against policy and the label against the boundary. But your most valuable data leaves on access you granted on purpose. Every move is permitted. The dangerous one passes the check like all the others. The breach is not in any single action. It is in the shape across moves: the same approved channel, an unusual hour, an unusual volume, an identity whose job does not normally touch those paths. A policy engine that scores one action at a time cannot see a shape made of many.
Where Hilt adds a layer
Hilt sits underneath the application, at runtime, on the movement itself.
One lightweight collector watches data movement at the kernel, metadata only by default, off the path. Call it 0.1% of one core and 4 to 8 MB of memory per host. It never sits inline. It does not block, drop, or alter traffic, and it does not have to read your data to do its work. Content-aware inspection is there when you want it. It is not the price of entry.
Each move resolves to a probabilistic, source-dependent identity: which workload or user, which job drove it, which destination, and whether this fits what that identity normally does. The vantage is the kernel, not one application, so the view does not end at the edge of the Microsoft estate. A database read, a cross-cloud transfer, an agent reaching into a system of record, a copy to object storage are one kind of event to the collector. All movement. Movement is what it scores.
An identity that normally touches three internal paths starts reading high-value data in a new shape, off-hours, toward a destination with a volume profile nobody has seen from it. The deviation surfaces across layers at once. Any one signal is noise. Together they are a case, not an alert. Hilt writes the case and, when the move warrants it, responds with host-level network isolation, quarantine from the control plane. It never filters packets inline.
Purview does not occupy this layer. Suite-native governance checks permission inside the surfaces it owns. The runtime pattern of movement across every surface is a different question, and it needs a different vantage.
Where Hilt does not replace Purview
Hilt does not classify your documents or apply sensitivity labels. It keeps no data catalog and no lineage map of your M365 estate. It does not run eDiscovery, retention, or your compliance reporting against Microsoft-centric frameworks. It does not govern SharePoint sharing or stop an outbound Outlook message. Those are Purview's jobs, and Purview does them. Hilt is not the tool for any of them.
Hilt adds the runtime layer beyond the suite: movement visibility across cloud workloads and user endpoints, resolved to identity and job, scored against how your data actually moves, single-tenant in your own cloud so events never leave your account. Purview governs the Microsoft estate, the labels and the policy, the surfaces it owns. Hilt watches the move itself, everywhere data flows, and catches the pattern across moves that no permission check is built to see. The two stack.
How to decide
Your data lives inside M365 and Azure, and your question is classification, labeling, retention, application-layer DLP. That is Purview. Hilt changes nothing there.
Your most valuable data moves through production workloads, between clouds, into AI agents, and out through connections you opened on purpose, and you want to see the dangerous pattern while it forms instead of reading about it in a disclosure letter. Purview was never built to cover that layer. Hilt covers it and replaces nothing you already run.
So the comparison resolves to "Hilt and Microsoft Purview," with a clean line between what the suite governs and what runtime movement governance watches across everything else.
Want to see where that line falls in your own stack? The fastest path is a 30-minute technical call, engineer to engineer, walking through what the collector would see and where it sits next to what you already run.