Because rapid application development eschews costly planning and regimented linear models in favor of an approach in which changes can be made during any development stage, it is often grouped together with Agile development. But while RAD incorporates many Agile principles, it is not the same thing.
Agile focuses on breaking projects down into features built during sprints (short periods where a team works to complete a predetermined set of tasks), creating multiple iterations designed to produce feedback as each feature is completed. RAD, on the other hand, places greater focus on prototypes—usable versions of the complete product that can be shared with the user to generate more feedback relevant to the entire app. Rather than waiting for individual features to be completed before seeking user assessment, RAD delivers prototypes still in the development phase so that full functionality may be improved throughout the entire process.
To do this, RAD relies on an extensive repository of reusable code to create and release prototypes quickly, so that the development process remains focused on creating and refining usable software.