3 Requirement Types in Software Engineering – Explained Like I’m 5

3 Requirement Types in Software Engineering Explained Like I’m 5

If you’re new to requirement types in software engineering, these are conditions that software developers use to figure out what a piece of software should do.

When a client comes to a developer with an idea for a piece of software, the developer uses requirements to understand how the software will perform, what features it will have, and how it will work. 

This information gives the software developer a roadmap to build against.

Let’s go over why requirement types in software engineering are important, 3 common types used during development, and examples of each. 

Why Are Requirement Types in Software Engineering Important?

In order to create software that meets the expectations of the end-users, developers must first understand what the impact of the software will be, what customer needs are being met, and how users will interact with the software.

By outlining these through a set of requirements, this helps flesh out the basis of the software design, as well as, prioritize the requirements that are necessary for the success of the software

Here is an easy way to think about it:  When a contractor is hired to build a house, they need to know the structural requirements, such as the number of floors, rooms, and doors and windows required. 

They also need to know functional requirements like what kind of heat or thermal insulation is needed, or what security system will be put in place to protect against burglary. 

They may also want to factor in user requirements, such as the need for left-handed door knobs or disability ramps. This is an example of groupings of requirements for home building. Similarly, requirement types in software engineering provide the what, why, and how of the software being created.

3 Types of Requirement Types in Software Engineering

Since there are so many different types of requirements, we’re only going to focus on 3 of the most common ones. 

1. Functional Requirements

A functional requirement describes what the software must offer or what it must be able to do.  

These requirements capture the system’s intended behaviour, so for example, an inventory tracking program may have a functional requirement to be able to generate reports on the inventory. It’s important to note here that a functional requirement can be expressed as a specific function, or as a task or service that the software must perform.  

Other common functional requirement types in software engineering may include: handling transactions, providing certification requirements, running audits, or providing historical data management. 

2. Non-Functional Requirements

Non-functional requirements are usually expressed as qualities or characteristics that the software must have.  

For example, a non-functional requirement for a warehouse’s inventory program would be to have the capacity to handle large data volumes without crashing, and must be secure. 

Other common non-functional requirement types include: performance, security, maintainability, portability, compliance, and usability.

3. User Requirements

User requirements are pretty much exactly what they sound like – they detail what the user of the software expects to be able to do. 

While user requirement types in software engineering can be classified as functional or non-functional, they should be kept separate as lumping them in with these two categories can cause the developer to miss key insights into the expectations of the user. 

In following our inventory tracking software, a user requirement might be that the software needs to be able to add and remove items from the inventory, as well as edit existing items. User requirements will often be specific to a certain type of user – so for example, an administrator user might have different requirements than a regular user.

Other common user requirement types in software engineering may include: being able to add a new customer account, be able to view order history, check order status, or have 20 users on the system without causing delays. 


When it comes to requirement types in software engineering, the key takeaway here is to look at them as the framework in which software is designed against.

They help to set the stage so that when it comes time to design and build the software, it meets the needs of everyone involved. 

A great way to tackle building an effective documentation of your software’s requirement types is by using a tool like Trello

This is a project management platform that can help your developers collaborate on code, organize large projects with less stress, and keep them agile in solving complex requirement types. 

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