The goal is to transform the design into executable code and to perform a basic level of testing, in particular unit testing. Primary activities include:

• Understanding and evolving the design model
• Writing program source code
• Implementing components, services, and/or modules
• Design of components, services, and/or modules
• Unit testing source code
• Integrating the code into subsystems and/or a deployable build

Before any building can occur, consideration needs to be given to how and where a package will be built (bearing in mind other build activities that are being performed) The environment for package build might be an existing environment or a new environment. For large complex projects the environment required might be a major development in its own right.

Components are constructed from the designs established in Design activity. Components are usually individually tested before assembly into a package and the development of end-user documentation.

Activities include:

• Software is coded.
• Code is reviewed
• Data is documented.
• Services are documented.
• Processes are documented.

Examples of software coding methods include the following:

• Structured programming
• Object-oriented programming
• Automatic code generation
• Software code reuse

All work should be done to software coding standards including

• Language standards
• Naming conventions for variables
• Structure and hierarchy of software product components
• Format of code and comments

Coding criteria might include the following:

• Modularity
• Clarity
• Simplicity
• Structured (e.g., no GOTOs, one entrance, and one exit)
• Maintainability

Work should be verified (peer reviews or pair programming).