Open standards and interoperability
In shortAn open format is the cheapest exit there is — it costs nothing and works immediately.
A standard is open when three things hold: the specification is freely available, it may be implemented without a licence fee, and more than one vendor has actually implemented it. Without the third, it is documentation, not a standard.
What it settles
The list is short and looks banal until you hold it against your own estate.
- Documents: ODF and PDF/A rather than vendor-dependent formats.
- Mail and calendar: IMAP, SMTP, CalDAV, CardDAV. A mailbox that speaks these can move in a weekend.
- Sign-in: OIDC and SAML. With those the identity provider is replaceable without rebuilding every application.
- Object storage: the S3 interface, which practically every European provider supports.
- Containers: OCI images and Kubernetes.
- Invoices: the European norm EN 16931, in Germany as XRechnung and ZUGFeRD.
If you are allowed only one question when buying something new, this is the one: in what format does our data come back out, and who besides you can read it?
The difference between export and interoperability
An export is an event. Interoperability is a state: two systems working on the same data in parallel. That is why a migration on open formats can run in stages, while one without them has to end in a cutover — with everything that goes wrong on a cutover date.
What the Interoperable Europe Act adds
Since 2024 it obliges public bodies to run an interoperability assessment before major IT projects and to publish solutions for reuse. It does not apply to companies — but it makes public demand more predictable, and which European products get built at all hangs on that. See Public money, public code.