Functional vs Non Functional Requirements
The Key Difference Between Functional and Non functional Requirements is that Functional requirements describe what the system or software is supposed to do, whereas Non-Functional requirements describe how the system or software should perform.
Comparison Chart
- Functional and Non functional Requirements both have different features and functionalities, here is a comparison of some key features between them.
| Functional Requirements | Non Functional Requirements |
|---|---|
| Functional requirement describes what a software system should do. | Non-Functional requirements describe how the system or software should perform |
| Functional requirement is specified by User. | Non-functional requirement is specified by technical persons. |
| Functional Requirements is mandatory. | Non Functional Requirements is not mandatory. |
| Functional requirement is describing the behavior of the system as it relates to the system’s functionality. | Non-functional requirement elaborates a performance characteristic of the system. |
| Verify the software’s functionality | Verify the software’s performance |
| Functional testing such as API testing, system, integration | Non-Functional testing such as usability, performance, stress, security, etc |