The product owner is responsible for what goes into the product backlog and prioritizes it. The product owner also represents a project’s key stakeholders and makes sure that group’s interests are at the forefront. Individuals with top-notch communication skills and market insight usually make the best product owners.
The Scrum Master is the team facilitator or “servant leader”. This person ensures teams have what they need to get the job done and sets up meetings to coordinate efforts. Rather than possessing management authority, these individuals empower their colleagues to work more efficiently with each other and related departments.
Developers & Testers
Developers & testers write code and make sure it does what it’s supposed to do. In an agile environment these individuals are free to choose whichever development method they think is most suitable for a situation. Without static, prescribed systems, developers have more room to innovate within the code.