Agile software development refers to a group of software development methodologies{.mw-redirect} that are based on similar principles. Agile methodologies generally promote: A project management process that encourages frequent inspection and adaptation; a leadership philosophy that encourages team work, self-organization and accountability; a set of engineering best practices that allow for rapid delivery of high-quality software; and a business approach that aligns development with customer needs and company goals.
There are many specific agile development methods. Most promote development iterations{.mw-redirect}, teamwork, collaboration, and process adaptability throughout the life-cycle of the project.
Agile chooses to do things in small increments with minimal planning, rather than long-term planning. Iterations are short time frames (known as ‘timeboxes’) which typically lasts from one to four weeks. Each iteration is worked on by a team through a full software development cycle, including planning, requirements analysis, design, coding, unit testing{.mw-redirect}, and acceptance testing{.mw-redirect} when a working product is demonstrated to stakeholders. This helps to minimize the overall risk, and allows the project to adapt to changes more quickly. Documentation is produced as required by stakeholders. An iteration may not add enough functionality to warrant releasing the product to market, but the goal is to have an available release (with minimal bugs) at the end of each iteration. Multiple iterations may be required to release a product or new features.
Some principles of Agile Development
- Customer satisfaction by rapid, continuous delivery of useful software
- Working software is delivered frequently (weeks rather than months)
- Working software is the principal measure of progress
- Even late changes in requirements are welcomed
- Close, daily cooperation between business people and developers
- Face-to-face conversation is the best form of communication (Co-location)
- Projects are built around motivated individuals, who should be trusted
- Continuous attention to technical excellence and good design
- Simplicity
- Self-organizing teams
- Regular adaptation to changing circumstances
You can get more information on Agile Development from,
https://en.wikipedia.org/wiki/Agile_software_development and https://msdn.microsoft.com/en-us/architecture/bb404166.aspx