User requirements

Business requirements

Functional requirements

Non-functional requirements

A restriction that is imposed on the choices available to the developer for the design and construction of a product.

A high-level business objective of the organization that builds a product or of a customer who procures it.

A description of a behavior that a system will exhibit under specific conditions.

A description of a property or characteristic that a system must exhibit or a constraint that it must have.

A high-level business objective of the organization that builds a product or of a

customer who procures it.

A top-level requirement for a product that contains multiple subsystems, which could be all software or software and hardware.

A restriction that is imposed on the choices available to the developer for the design and construction of a product.

A description of a connection between a software system and a user, another software system, or a hardware device.

To ensure the software is developed without any user involvement

 To clearly understand and define what the software is expected to achieve.

To reduce the need for software testing later in the project

To speed up the coding phase by skipping documentation