Analyses how a project-based firm builds project capabilities for digital delivery on complex projects. Articulates how the project-based firm aligns the set-up of digital delivery on the complex project with the firm’s related project capabilities. Articulates how the project-based firm reconciles differing agendas and capabilities during project implementation. Argues that aligning and reconciling are important in creating the relative stability needed to build project capabilities in the ecology of a complex project. Finds that building these capabilities involves both ‘economies of repetition’ as well as ‘economies of recombination’.