Extensibility is a characteristic where the architecture, design, and implementation actively caters to future business needs.

Extensible applications have excellent endurance, which avoids the expensive process of procuring large inflexible applications and retiering them due to changes in business needs. Extensibility enables organizations to take advantage of opportunities and respond to risks. While there is a significant difference, extensibility is often confused with modifiability quality. Modifiability means that is possible to change the software, whereas extensibility means that a change has been planned and will be effortless. Adaptability is at times erroneously leveraged with extensibility. However, adaptability deals with how the user interactions with the system are managed and governed.