JIRA, Scrum, Full Stack: Scrum: Roles

Product Owner

1. Responsible for the product vision.
2. Person who maintains the product backlog.
3. Only person who can make a decision whether the product is ready to ship.
4. Only authoritative person to take a decision about abruptly discontinuing/stopping the sprint.
5. Person responsible for providing clarification on the user story to the development team whenever needed.
6. Only authoritative person to take the decision of including any further functionality to the product backlog.
7. Person to constantly reprioritize the product backlog. 

Scrum Master

1. Facilitator of the Scrum process.
2. Helps resolving any issues / impediments faced by the Scrum team.
3. Shields the team from external interferences and distractions.
4. Creates a positive environment for the team to be self-organizing.
5. Enforces timeboxes.
6. Person who maintains sprint burn-down / burn-up charts.
7. Person who facilitates the required meetings.
8. Has no management authority for the team (for example, he or she cannot command the team to do a specific task).
9. Promotes improved practices of engineering.
10. Only Point-of-Contact for escalations.
11. Only person who can take the escalations or request to the top management. 

Development Team

1. Consists of 7+/- 2 members.
2. Should be a self-organizing and cross-functional team (consists of the members with testing, development, business analyst, domain expertise, etc., skills).
3. Should self-manage the tasks among the team.
4. Should resolve people management issues if any among the team and should only take it to the Scrum Master if it has gone out of the team’s control.
5. Works with Product Owner in reprioritizing the product backlog items.
6. Responsible to complete the committed task for the sprint.