Realizing a design through

  • Writing code and/or scripts
  • Configuring existing components
  • Testing at various levels

are activities normally associated with the implementation phase. At implementation, all interfaces should be defined, the project's technologies are likely fixed, and the scope of deployment known.

The term implementation also refers to the process of integrating a (supposed working) software product into an existing system and/or business process, something that could also be called a maintenance task.