Writing a Comprehensive App Requirements Documentation: Guidelines and Useful Tips

Maryna Pasko
Market Researcher

The world is more digitized than ever before, and to keep up, enterprises need to join and actively participate in the digital revolution. Whether you’re launching a promising startup or helping an existing business go digital, mobile app development is essential to gain business and stay relevant.

If you’ve decided to build a mobile app, you probably have an innovative idea and a vision of how the application will function. If you can describe in detail how the app should look and perform, congratulations, that’s a great start! 

The next logical step is hiring skilled professionals to develop your app. After monitoring the market, you finally found the best app development company, and you’re eager for the work to begin. 

 But that can’t happen immediately,  first, you need to describe every aspect of your desired app to developers so they understand exactly what to build. 

To ensure your requirements are met, you’ll need to create a mobile app development requirements document. This task can seem a bit challenging, especially if you've never done it before.

To help you outline your app idea clearly, here we cover the essentials of a comprehensive app requirements document. 

Before we get stuck into the details, let's review some of the basics. 

What Is a Mobile App Development Requirements Document?

An app requirements document is a comprehensive overview of an application idea. It should contain a detailed description of the concept, objectives, and scope of your project. The technical part of the document must include characteristics of any features in your application and the corresponding functional requirements. 

Most of an app requirements document is text, but graphics such as wireframes and sketches can help illustrate your needs.

Why an App Requirements Document Is  Important

A well-written, comprehensive document clearly presents a vision of your project. Based on this document, developers create the product backlog and organise the whole development process.  

Creating an exhaustive app requirements document is crucial for you, as a business owner, and for the developers who work on your project. They use the document as a guideline to build the app per your expectations. So it’s important that your mobile app requirements document is readable, clear, and explanatory. 

Now, let's move on to creating an app requirements document. 

Building a Mobile App Development Requirements Document: Five Essential Steps

First, you should know that there is no one "right" way to write an app requirements document, so it’s entirely up to you how to structure the document. What matters is giving your developers precise information on the final product you expect. 

That said, when composing an app requirements document, the five-step guide below can help.


Describe your idea and objectives

Start the document with a brief description of the central idea of your app. For example, if you want an app that rates the attractiveness of dog breeds, let your potential developers know that at the beginning of your document. Additionally, you can say a few words about the main features and functionality you require.

 Try to explain in a few sentences what you want the app to do and present its core objectives. A tight, brief introduction clearly sets out the app’s key concept and what you need from the developers.

Conduct market research

If you want your product to be successful and profitable, robust market research is essential. 

Identify the needs of your target audience and think about how your app can satisfy these. Researching potential users’ ages, locations, occupations, and interests helps you create workable user personas. In turn, these user personas offer a better understanding of the future app’s functional requirements. For instance, if your app-to-be is the world's largest knitting pattern repository, you may discover that your target user will value X feature while Y feature is of less importance.

In this part of the document, you can also add information about the niche you intend to occupy and your closest competitors, including the platform, the approximate number of users, and any other helpful details.

Choose features

After researching the target audience, you’ll have a more explicit picture of the user's expectations. From there, you can start planning the features required to meet the user's needs. 

The best solution for the initial version of your app is to offer a simple and intuitive user experience with few key features. Such an approach is essential when building a minimum viable product (MVP). In this case, you need to be very selective with the features you choose. 

To validate and prioritize features, try the  MoSCoW method. Divide features into four "have" categories: must, should, could, won’t. This analysis separates features directly related to business goals from others that are inessential and can be postponed until later iterations of the app.

With the finalized list of features, developers can determine the integrations, APIs, and third-party elements needed.

Prepare functional specifications

Functional requirements provide an exhaustive description of the functions and features of your application. They also explain how the app should perform and respond to user requests. Properly composed functional requirements clarify exactly how the app’s features solve user problems. 

This part of the document must also encompass the mobile app’s technical specifications, such as the platform for launching the app, development tools, description of the app’s interaction mechanism, collaboration with the server, protocols, and data. If you are unable to complete this section yourself — it’s not a big deal. Your developers can assist you with this matter.

Apart from this, your functional requirements section may include information on the project’s scope, risks and assumptions and so on. 

Provide wireframes

Sketches and wireframes of your app’s screens give a visual representation of the requirements and make things clear. Wireframes help developers understand how your future app will work, and show the relationship between different features and functionalities. 

You can ask professionals to draw the screen blueprints or do it yourself.  You don’t need to be a graphic designer and there are plenty of tools for creating fast and simple sketches. Technologies like Axure RP, Balsamiq, Figma, Sketch can help you make visual representations of your app’s navigation and structure.

Consider The Non-Functional Requirements

Unlike functional requirements that define what the system does, non-functional requirements specify how the system does it. They describe the system's operational capabilities and provide guidelines on how to build the app correctly. 

Here are some of the main non-functional requirements you should consider:

  • Performance: Performance is measured by response time: the faster the system returns results, the better the performance.
  • Scalability: Is how well your app handles high workloads and increased user data (stored data, caches).
  • Responsiveness: The app should respond to the user’s input or external interrupt and return to the same state. 
  • Usability: This criterion defines the quality of the user experience (UX). Users should be able to understand the app’s functions without guidelines or other assistance.
  • Reliability: A probability percentage of an app working without failure and delivering expected results for a given time under certain conditions.
  • Security: All app data (especially user contacts, payment methods, etc.) must be secured and encrypted to protect against malware or unauthorized access.

When including non-functional requirements in your mobile app development requirements document, make sure they are measurable, testable, and correlate with your business objectives.

Additional Tips on Writing a Comprehensive App Requirements Document

We’ve already spoken about the importance of a mobile app requirements document and mentioned the essential information it should include. But before you start writing, here are some helpful tips on creating an exhaustive and reliable app requirements document.

Make the document comprehensive and clear

Keep in mind that besides the development team and yourself, your requirements document might be read by other people, for example, investors. Therefore, try not to overload it with narrow-profiled technical terms and keep the language simple to understand.

Ensure each requirement is testable

Writing a requirement with a test scenario in your head is beneficial for you and your developers. It gives your designers and test engineers a clear picture and thorough understanding of what exactly needs to be done. Ensure each requirement is clear, measurable, and the specification is verifiable.

Write in an implementation-neutral manner

By writing your document in an implementation-neutral manner, you won't have to write about the design in detail. If you modify implementations in the future, you won't have to rewrite the requirements from scratch. 

Finalise the requirements document with team members

After you’ve compiled your app requirements document, evaluate it with your product development team. Engaging designers, developers, and quality assurance engineers in the process increases the chances that the specs will comply with your needs.

Well, that’s pretty much it. If you consider all the above points and implement them in practice, you’re well on your way to a flawless app requirements document. 

However, if things are still unclear or you’re feeling overwhelmed, a mobile app development requirements document template could be just the ticket.

Is Using a Template a Solution?

A generic app requirements template isn’t a universal solution because mobile apps differ significantly in both concept and complexity. 

Instead, browse a variety of mobile app requirements documents and use the most suitable one as a basis for your document. You can edit the template by adding required details or removing irrelevant information. As a result, you'll get an app requirements document template that fits the specifics of your project.

It’s hard to underestimate the significance of an app requirements document in a project. Well-written documentation serves as a foundation for a successful product that gets the development process off to a great start.

We hope this article was helpful. At MadAppGang, we provide tech-savvy mobile app solutions, including project planning services. Take a moment to learn more about our services and products, and if you’re interested in cooperating, reach out before starting on your next project. 

03 March 2021 app development requirements document