Understanding Functional and Non-Functional App Development Requirements

Understanding Functional and Non-Functional App Development Requirements

Did you ever consider that unclear requirements eat 41% of a company’s IT development budget? Indeed, these ambiguous criteria increase development expense and timeline estimations by 60%! This could imply that the damage has already been done before you begin the endeavor.

That is why today’s post is so important. As projects progress and deadlines approach, some seemingly non-essential features are unavoidably abandoned by the client. This is done to save both time and money. These non-essential needs are usually non-functional requirements.

Now, if you could find a means to categorize essential and non-essential requirements from the start, you might commit a portion of your resources to the essentials while not losing any progress made on the non-essentials if they are discarded.

That is why knowing functional and non-functional needs is critical for all stakeholders involved in App Developers Vancouver. This shortens projects, saves money, lowers waste, resulting in a more holistic, well-rounded development, and gets the product to market faster.

So what are functional and non-functional requirements?

Functional Requirements

Simply, functional requirements specify what an app is expected to achieve. They are the essential functionality without which the app would not work or perform as intended.

These are prerequisites that must be met and cannot be skipped. These needs must be explicitly expressed and documented in a development contract before work can begin. They must be recorded as inputs to the system before the operation is completed and the output is delivered to the user.

Here are some instances of functional requirements:

  1. Authentication
  2. Business core
  3. Transactions, checkouts
  4. Authorizations
  5. Historical data

Non-functional Requirements

Non-functional requirements are those that specify ‘how’ the program must fulfill a specific function. In essence, these are the app’s quality attributes that determine the app’s user experience. They are also known as non-behavioral requirements and must be implemented in the order of importance to the React Native for Mobile App Development function. This makes them somewhat flexible, as it is feasible to bypass a few due to time, budget, or technical constraints.

Non-functional needs include the following:

  • Loading speed
  • Time taken to deliver server response
  • User response time
  • Data consumption limits

Time to put this all in perspective. For example, the functional requirement for a food ordering app would include:

  • Displaying restaurants in the area
  • Displaying menus
  • Placing orders
  • Processing transactions, etc.
  • Non-functional requirements of the food delivery app would include:
  • Refresh restaurant listings every 5 minutes
  • Load menu within 10 seconds of clicking on menu button
  • Order confirmation must be sent within 2 seconds of payment

As the name implies, functional requirements are essential components of an app that must be incorporated in the development process. Is this to say that non-functional requirements aren’t important after all?

Non-functional requirements are critical to the app’s performance and user experience. If a functional requirement of an app is to retrieve a list of sushi restaurants in the neighborhood, but the app takes more than 30 seconds to do so, the user is likely to exit the app, even if the functional demand was eventually met.

So, establishing a proper balance of functional and non-functional criteria is vital to ensure that an custom software development service project is successful, under budget, and on time. This manner, if you need to drop any app attributes, you can quickly pick which ones to preserve and which can be excused for the time being.

Why differentiate between functional and non-functional requirements?

On the surface, the delineation is clear. It appears that distinguishing between functional and non-functional criteria is a no-brainer. So, why is it critical to properly collect, classify, and document these?

To keep the development cycle moving smoothly and avoid lengthy reviews later on, it’s critical to precisely classify functions and understand what you’re dealing with.

According to one study, 68% of projects that follow good communication and proper documentation are more likely to satisfy project criteria.

Another survey indicated that 32% of IT projects were reported to fail owing to unclear requirements, making them one of the leading causes of IT project failure. Uncertain requirements result in capital waste, missed deadlines, and a lower-quality product overall.

To avoid this, it is critical to specify the project scope and requirements. This necessitates explicitly defining functional and non-functional needs in order to establish development priorities.

Understanding functional and non-functional requirements is beneficial to us.

Improve communication – Clarifying requirements ensures that all teams and stakeholders are on the same page. This eliminates any gaps or misunderstandings later on.

identify roles and goals clearly – when all criteria are articulated clearly, it is easier to identify team roles and who performs what.

Estimate more precisely – knowing what features will be included in the app allows for a more precise estimate, both in terms of cost and time.

Catch problems early on – reviews tend to get more expensive as time passes. Early detection of errors saves time, money, and morale, leading in better app development.

It helps you to maintain a few non-functional requirements flexible by knowing your functional and non-functional requirements. If some features must be discarded due to budget or time constraints, you’ll know exactly what you must keep and what may be omitted.

Role of Prototypes in Defining Requirements

Now that you understand how vital it is to understand your requirements and distinguish between functional and non-functional requirements, it’s time to learn how to make sense of this information.

Building a mobile app prototype is one of the finest methods to keep a clear project goal and everyone on the same page. This allows you to get as close to picturing a real app as possible without having to write a single line of code. Knowing what else you have room for depends on your ability to visualize all of your functional requirements as well as the significant non-functional requirements. This allows you to chart out a clear plan of action and understand how your solutions will function.

How to Define Non-Functional Requirements

This is the tough part. Non-functional needs, in contrast to functional requirements, can be difficult to define. There are several that we believe everyone is aware of, such as sending confirmation emails within 5 seconds. However, if those are not explicitly stated, there will be a catch situation in which confirmation emails will be delayed when networks fail, resulting in a very unpleasant user experience.

As a result, it is critical to precisely specify any non-functional needs at the outset of your project. Some ideas for doing so include:

Make a list – first and foremost, sit down with the stakeholders and your team for a brainstorming session with all ideas on the table. Make a list of them all before you start categorizing.

Use pre-defined classifications – You might simply categorize the various non-functional requirements under pre-defined classifications such as operation, business, and administrative. This will help you prioritize and determine what needs to be done first.

Use automated testing – Selenium, Appium, Test Complete, and other automated testing tools can help you swiftly examine the performance of your project, identifying any non-functional needs you may have overlooked.


Every resource is valuable when it comes to business app development. Understanding your functional and non-functional needs can save you time, money, and human resources while developing an app. Clearly defining functional and non-functional needs is analogous to having a precise plan with pit stops marked out. This way, you’ll know precisely how long you need to keep that can of Coke down.

At Linkitsoft, Once you’ve determined your requirements, you may begin working on the functional requirements straight immediately, leaving room for changes based on iterations and customer input. When it comes time to trim deadlines and drop a few frills and whistles, you’ll know exactly which components you want to maintain.

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