Prexfo — the open data standard for the real estate industry #
Today, property data lies scattered across management software, portals and cloud services — every vendor in its own format, every switch a loss of data. Prexfo turns this around. The database is no longer the source of truth; an open, versioned file-and-folder structure is — and it belongs to the owner. Databases become a replaceable cache. The vendor can change; the data stays.
Prexfo stands for two things that belong together: the PropertyExchangeFormat — an extensible XML schema for structured data exchange — and the PropertyExchangeFolder — a standardized folder structure for local data keeping. Together they form a complete, auditable history across the entire lifecycle of a property: from planning through maintenance, tenant changes and modernization all the way to sale.
The idea #
Data sovereignty, decentralization and lifecycle — why a file-based standard beats the cloud, and how AI becomes a tool without raw data ever leaving the building.
The format #
PropertyExchangeFolder and PropertyExchangeFormat in detail: the folder structure as the data model, the XML schema with clean versioning, and the PDF/A-3 container following the proven ZUGFeRD model.
In practice #
Prexfo is not a whitepaper. At Berlus, 106 properties and more than 178,000 documents run in the format in production — full-text searchable, machine-readable, in our own hands.
Why another standard? #
Because none of the existing ones fit. OpenImmo stops at marketing. IBPDI is a monolithic, platform-bound behemoth. BIM/IFC describes the building, not its operation. Between the highly detailed building model and the superficial sales listing lies a gap: the property as a living, economic asset, over decades. That is exactly where Prexfo comes in — pragmatic, open, and with uncompromising data sovereignty.
Three principles, one promise. Data sovereignty instead of vendor lock-in. Offline-first instead of forced cloud. GDPR-compliant by design instead of a retrofit. Schema and SDK are released under Apache 2.0 — the standard belongs to no one, and therefore to everyone.
Who Prexfo is built for #
For property managers who no longer want to pawn their data to a piece of software. For banks and insurers who need audited, comparable data for fast risk decisions. For service providers who receive exactly the property data they need for a quote — no more, no less. And for PropTech developers who build specialized tools on an open foundation, instead of the tenth all-in-one management suite.
Our principle: The standard is not born on a drawing board but in operation. What Prexfo promises, we put into practice at Berlus first — and we show openly what works and what is still open.