Coalition data sharing fails in a predictable way. Everyone agrees to share, nobody agrees to give up control, and the compromise is a liaison officer carrying a hard drive between two rooms.

A data fabric is worth building only if it solves that, which means national caveats have to be enforced by the system rather than by goodwill, and only the minimum necessary data should ever cross a boundary.

Agree the contract, not the database

Each exchange is defined as a mission data contract with a standards-based serialisation, so partners integrate against a published interface rather than against each other’s internal models. Nobody has to adopt anyone else’s architecture to take part.

Put the policy on the data

Access is decided on attributes rather than network position, using XACML, with confidentiality labels bound to the objects themselves per STANAG 4774 and 4778. A caveat that travels with the object survives being copied; a caveat that lives in a server configuration does not.

Move it predictably

Deterministic quality of service, streaming bridges between the messaging technologies partners already run, and conformance tested continuously rather than declared at the start of an exercise.

Keep proving it

Interoperability testing runs as part of the build, supply chain is checked against a bill of materials, and the posture is zero trust throughout, following NCSC guidance. The payoff is a faster coalition decision cycle that is still auditable afterwards, a lower integration bill each time a partner joins, and sharing that respects sovereignty because the system will not let it do otherwise.