Scrum defines 3 distinct roles that form the Scrum Team, each with specific responsibilities that balance one another.

• The Product Owner represents customer and business interests, prioritizing the Product Backlog to maximize value. They make tough decisions about what to build first, balancing short-term needs with long-term vision. Effective Product Owners remain accessible to the team, provide clear acceptance criteria, and shield developers from shifting priorities mid-sprint.
• Developers (the Development Team) build the product increment. Cross-functional and self-organizing, they determine how to implement features, estimate work, and ensure quality. While specialized skills exist within the team, collectively they share responsibility for delivery.
• The Scrum Master serves as a coach and facilitator, helping everyone understand and apply Scrum effectively. They remove obstacles, facilitate ceremonies, and promote continuous improvement. A good Scrum Master leads not through authority but by influence, focusing on team effectiveness rather than individual productivity.

These roles create a system of checks and balances that prevents common product development problems like scope creep, siloed work, or disconnection from customer needs.