How to Write Good Software Requirements Specification for Your Mobile Application Development Project


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Considering custom mobile app development services, you probably stumble upon the term ‘software or mobile app requirements document’ too often. In case you’re looking for how to write a software specification documentation, this article is for you. For experienced technology companies like Dashdevs, this type of a technical design document for mobile applications can be par for the course. However, if you aren’t involved in software engineering, mobile app requirements gathering and structuring can be confusing, tedious, and rather troublesome.

Working closely with stakeholders at startups and SMEs, we know that a software requirements specification example for mobile applications can quickly turn into a lengthy and overcomplicated document, making it particularly vulnerable to mistakes and misinterpretations. Nevertheless, when done well, it will make sure that your team and business partners are all on the same page regarding your project’s scope, objectives, roles, and deadlines. Unfortunately, too often, business owners try to omit this step since they don’t want to hire an external company to take on this task or spend time on it inhouse. However, this leads to exceeding the original estimates, the rise of missed expectations, and schedule overrun. This is precisely why, at Dashdevs, we write specifications for every project and approve them with our clients.

Although there’s no universal approach to mobile software development, we share our internal best practices that will help you reduce the likelihood of errors, streamline the process, and guide to more effective outcomes.

What’s a Software Requirement Specification in Software Engineering?

Let’s start with outlining a software requirements specification definition (SRS), what this document should contain, and why we use it on our projects.

What’s a software requirement documentation? — In simple terms, it’s your product idea written on paper. A good SRS example for mobile applications includes information on what needs your solution covers, what features it should have and how they should work, what load it should resist, or when a finished product should be delivered. It gives a comprehensive overview of all functional and non-functional requirements of a project.

A well-written software application requirements document helps to break the problem down into smaller parts and improve the quality at each step, makes it clear to the tech partner or application development outsourcing provider what issues the solution should address and how, and accelerates testing and validation stages. Moreover, writing product characteristics and requirements in the scope statement, business owners can get more accurate cost estimates for app development, optimize the engineering process, minimize financial risks, and thus, shorten their time-to-market.

Types of Requirements in Custom Application Specification Development

A well-structured and unambiguous product specification document is an important sign on the road to a successful project. It serves as a formal agreement between a business customer and a contractor and makes sure that both are working toward a common goal.

At Dashdevs, we recommend our clients to hold at least 2 online or face-to-face meetings with their application development partners to discuss the requirements and expectations. During such discovery workshops, our team interviews product stakeholders, if necessary, conducts market research, and comes up with suggestions on what attributes should be enlisted to make sure the product’s design and functionality are aligned with the needs of potential users.

While planning your mobile project, it’s essential to gather and structure the following types of project requirements:

Business requirements are crucial since they articulate the concept of the project and its benefits to the company. The latter point explains how the solution will yield revenue or cut down expenses, including the timeframes and exact sums. Meanwhile, the vision communicates its goals and how the product will solve particular business or user problems. All this helps software engineers to understand your business tasks and decide on the best implementation approach in terms of technology.

Business requirements gathering is the starting point for any software product development process since it’s impossible to proceed with the definition of key user requirements or functional units if business needs haven’t been described.

The user requirements document reveals what consumers expect from the solution. It should precisely and accurately define what the product should do, what features and integrations it should offer, and what constraints it may have. It may include use cases, UML diagrams, and user flows.

At the information-gathering phase, it’s important to identify user groups and collaborate with various customers to get a comprehensive view of the topic and get it over to the engineering team. The list of user requirements for software development should be approved by the stakeholders and domain experts.

The system requirements document describes each operation, defines how the system should behave, and specifies app functionality in a particular environment. It should also outline necessary safety provisions as well as requirements for the infrastructure integrity and scalability.

The paper can be rather detailed, so, for added convenience, it’s divided into functional and non-functional requirements. However, the two are tightly correlated. Therefore, when non-functional elements for mobile apps requirements are set out, you can elaborate functional specifications.

To avoid confusion, let’s examine the latter in more detail.

The Difference Between Functional and Non-Functional Requirements in the Native App Development Process

We’ve already answered the question “what is system specification in software engineering?”, as well as provided user and business requirements definitions. Now let’s proceed with determining what immediate system-related specs should cover to help your mobile development partner create the right product.

Non-functional requirements in software engineering describe system capabilities and criteria that improve its functionality. These may include:

  • Performance: How responsive should the system be? How fast should it respond to user actions? How much should system capacity change under a heavy load?
  • Usability: How easy/challenging should it be for your users to understand and utilize the app? Should the solution meet particular cultural and linguistic specifics?
  • Compatibility: What operating systems, browsers, software versions, and hardware should the solution run on? Should it be compatible with specific programs or processes?
  • Reliability: What parts of the system should be accessible for users under any conditions? How much time (minutes/hours) can it be down per month/week/day? Should customers be notified in case of unexpected systemic failure?
  • Security: Should the system be compliant with any particular standards like PCI-DSS, GDPR, CCPA, Open Banking, PSD2, or OWASP? How should the solution be protected against fraud and cyberattacks? Should there be different user roles or separate login flows?

And what are functional requirements? — It’s a comprehensive description of all the functions and features that your mobile app should include, how it should perform and respond to user requests. In fact, you need to specify software behavior under certain conditions using plain text, diagrams, schemes, and other visuals. It’s critical to document and share all the thoughts and vision for the project using convenient PM tools; otherwise, there’s a huge risk of being unheard or misunderstood. The most typical formats and elements are:

  • Use cases depict various interactions between the solution and users that result in achieving concrete objectives. Every user case consists of actors (users), system (functional requirements and behavior), and goals (expected outcomes). It should also provide your information technology business partner with the context, so it’s important to include a description, pre- and post-conditions, primary interaction flow, alternate and exception paths.
  • User stories describe software features from the end-user perspective, and the typical format is as follows: ‘As a [user type], I want [purpose] so that [reason].’ Each user story must come with testable and clear acceptance criteria — conditions that the application must meet to be approved by a product owner, customer, or stakeholders. Moreover, all user stories should comply with the INVEST quality requirements: Independent, Negotiable, Valuable, Estimable, Small, and Testable.
  • Work Breakdown Structure (WBS) is a visual paper that demonstrates how complex functional units can be split into smaller elements. In this way, business customers and providers can analyze each component independently and so build a complete picture of the whole project. Smaller functional units are often used to calculate a precise project cost estimation. Simply put, WBS for mobile application development is a good organization tool for your workflow optimization.
  • Wireframes/prototypes help to visualize the product idea and give a better insight into the core functionality and possible user experiences. A collection of sketches is the best way to determine the overall project scope, design user flows, and make early changes to prevent material losses.

Other software functional requirements may include the purpose of the project, general overview with your vision, assumptions, and business rules, as well as concrete constraints like system attributes, mobile development platforms or frameworks, and database criteria.

Writing a Comprehensive Product Requirements Specification Document: The Right Approach

Though there’s no universal approach to preparing a product specification sheet, there are a few rules and common ways to do it right for the first time.

#1 Keep it logical and organized

Before you get down to actual writing, spend some time outlining the document structure. In this way, you ensure consistency, a 360-degree view of the entire product ecosystem, and smooth collaboration of all the members in the integrated product development team.

Today business owners often opt for ready-to-use product requirements document templates because they save time and maintain coherence. However, app specification templates often turn into text-heavy, overcomplicated, and tedious long-reads, so we advise our partners to go for visual data, including but not limited to diagrams, schemes, and charts.

#2 Make your product development specification exhaustive

Your project documentation should be transparent and complete. We’ve already looked into different types of requirements in software engineering and what information they should include. Providing your software engineering partner with brief overviews for each, you eliminate the need for designers and developers to waste time on guesses or assumptions, and make sure that the delivered product will comply with the initial requirements.

#3 Product development requirements should be testable

Although it’s a pervasive rule, business owners fail to observe it too often. A testable requirement must be clear, unambiguous, measurable, and it should describe one function. Working on the documentation, make sure that your specifications are verifiable; otherwise, it’s nearly impossible to understand if they were implemented sufficiently.

#4 Remain neutral about the implementation

Writing product requirements don’t delve into implementation since SRS explains what the application should do, but not how it should do that or how it should look. Such an approach ensures a more beneficial and efficient design process and adaptive requirements that aren’t regulated by particular implementation instructions.

#5 Finalize documentation with the product team

As soon as all requirement gathering for mobile app specification is over, ask your product development team to review and evaluate the documentation, before the implementation begins. Thereby you improve team engagement into the process, their satisfaction, and thus, the chances that specs will be aligned with their needs.


Though for most companies writing product specification still remains laborious and confusing, it’s worth the effort. The investment will pay off by optimizing your iOS or Android application development process, answering all developers’ questions about the product, and facilitating the kick-off. On top of that, the mobile app development specification document proves its relevance in estimating the development costs, defining priorities, and setting up a schedule with major milestones.

Having a clear vision about the most common types of software requirements and approaches to defining product specifications, you can efficiently put this knowledge into practice to get the expected outcome. A good software requirement doc serves as a roadmap for developers. Need assistance with mobile app software requirements specification? We, at Dashdevs, will help you get the ball rolling. Our team offers a holistic set of mobile app development services, ranging from requirements elicitation and prototype design to architecting, full-stack development, and lifelong support.

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