Christian Brustad contributed to Altinn/app-lib-dotnet and Altinn/altinn-studio, focusing on backend and API development using C#. He implemented identity-claims-based logic for setting read status on organization-created instances, replacing value comparisons with direct claim checks to improve data visibility and security. This change reduced edge-case errors and enhanced maintainability by tying access control to user claims. In Altinn/altinn-studio, he upgraded the Altinn.Common.PEP package from v3 to v4, simplifying authorization request creation and ensuring compatibility with updated security requirements. His work demonstrated depth in authorization workflows and backend systems, addressing both maintainability and future extensibility in production environments.