Agile Software Development is a term used to broadly describe a set of practices and frameworks that were created based on the principles outlined in the Manifesto for Agile Software Development, which was popularized in 2001. The Manifesto aims to help builders improve their process of building software.

According to the Manifesto, the core values of Agile Software Development are:

1. Individuals and interactions over processes and tools,
2. Working software over comprehensive documentation,
3. Customer collaboration over contract negotiation,
4. Responding to change over following a plan. That is, while there is value in the items on the right, we value the items on the left more.

Based on these core values, there are twelve principles:

1. Our highest priority is to satisfy the customer through early and continuous delivery of valuable software.
2. Welcome changing requirements, even late in development. Agile processes harness change for the customer’s competitive advantage.
3. Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale.
4. Business people and developers must work together daily throughout the project.
5. Build projects around motivated individuals. Give them the environment and support they need, and trust them to get the job done.
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. The sponsors, developers, and users should be able to maintain a constant pace indefinitely.
9. Continuous attention to technical excellence and good designs enhances agility.
10. Simplicity—the art of maximizing the amount of work not done—is essential.
11. Best architectures, requirements, and designs emerge from self-organizing teams.
12. At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly.

There are a few common frameworks and practices that have emerged from these principles, including:

• Scrum
• Extreme Programming
• Feature Driven Development
• Pair programming
• Test driven development
• Stand-ups
• Planning sessions
• Sprints