The moment of truth comes before the change itself.

This is where we test whether the assumptions behind the design hold true in practice.

The validation approach depends on the migration strategy we have defined. It allows us to test the critical elements of the proposed architecture, identify deviations and understand their impact before they reach the production environment.

Validation is not about proving that the original design was perfect. It is about finding what needs to be corrected.

The validation environment is usually a controlled simulation — an abstraction of the production environment focused on the elements that matter. It gives us enough of the real conditions to validate the architecture, behaviour, dependencies and critical scenarios without reproducing the entire network.

The results may confirm the design, reveal deviations that can be corrected, or even take us back to the Design phase when the original assumptions no longer hold.