The 12 principles of the Agile Manifesto by Fowler and Highsmith (2001) are:

1. Customer satisfaction
2.  Welcome change in requirements
3. Delivering working software frequently, from a couple of weeks to a couple of months, with a preference for the shorter timescale
4. Business people and developers must work together daily throughout the project
5. Agile believes in a shared value approach in which customers are seen as collaborators
6. The most efficient and effective method of conveying information to and within a development team is face-to-face conversation
7. Working software is the primary measure of progress
8. Agile processes promote sustainable development
9. Continuous attention to technical excellence and good design enhances agility.
10. Simplicity—the art of maximising the amount of work not done—is essential.
11. The best architectures, requirements and designs emerge from self-organising teams.
12. At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behaviour accordingly