How to Write a Mobile App Requirements Document (+ Free Template Download)

In this article, we’ll talk about the critical role of requirements in mobile app development. What are the types of requirements and what’s the right way to develop them?

Scroll down and get a mobile app requirements document template to help you get started.

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Contents:

1. Why should you write a mobile app product requirements document
2. Types of requirements
3. Business requirements
4. User requirements
5. System requirements
6. Ways to develop and manage requirements
7. Characteristics of a good mobile app development requirements document
8. A mobile app requirements document template

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Why should you write a mobile app product requirements document (PRD)?

To turn your idea into a shippable mobile app, you need a team of developers. But finding the right team isn’t the hard part. The hard part is explaining your mobile app vision to developers so clearly that they conceive it the way you do.

The importance of writing a mobile app product requirements document (PRD) is that it helps you facilitate a meeting of minds between you and other stakeholders. Don’t balk at investing time in engineering product requirements, because the potential payoff is clear.

Let’s highlight core reasons why you should write a product requirements document for your mobile app startup:

• Increase your own certainty. Discussing requirements for your mobile app makes everything clearer. Objectives, perspectives, features, constraints — your product vision starts to take shape. Determining product requirements moves you from fuzzy statements to tangible tasks with thorough deadlines, budgets, and quality criteria.

• Make your ideas clear to developers. Clear product requirements reduce the expectation gap between the mobile app you want and what developers deliver.

• Get prompt development and delivery. With documented mobile app requirements in sight, your development team can better understand your project, set priorities, and reduce rework.

• Make sure the final app meets your quality expectations. Thanks to the acceptance criteria stated in a PRD, your team can easily determine whether you will be satisfied with the delivered app.

• Reduce scope creep. A high-quality requirements specification prevents you from developing unnecessary features, prevents your team of developers from working at cross-purposes, and guards your whole development team from becoming overloaded.

• Spend less. Since well-thought-out requirements contribute to a focus on the essentials, reduce rework, and speed up development, they save you money.

According to Boehm’s research, rework can cost about 40% to 50% of the total cost of all software development. And a major part of rework is caused by requirements errors. IBM once claimed this:

“Time not spent in requirements is time spent in rework — at 200 times the cost.”

Another advantage of clear requirements is that they allow your team to detect defects shortly after a product is created and fix them at a lower cost than in late development or after the app is released. So it’s important to take developing product mobile application requirements not as a wasteful and frustrating matter but as an investment in your project that will pay off in spades.

Types of product requirements

When you get an idea to make an app, you need to ask yourself three main questions:

• Why? Why do you need a mobile app? To help people with your unique experience, get an extra revenue stream, as an investment — what is your goal?
• Who? Who will use your app? Think of your target users’ pains, problems, needs, and preferences. What solution do users expect to get from your app?
• How? How will you achieve your desired business outcomes and meet users’ expectations? Think of the functionality your app should provide.

Answers to these questions form three main levels of requirements for mobile app development: business requirements, user requirements, and system requirements.

Each level also has an assortment of functional and non-functional requirements.

Functional requirements relate to your app’s operation and features you’re going to implement.

Non-functional requirements define characteristics and constraints that aren’t connected to functional requirements. In most cases, non-functional requirements relate to:

• Attributes of the developed product like performance, reliability, availability, and usability.
• The app development process, describing development methodologies, standards, coding languages, time restraints, security, etc.
• The external environment, taking into account your app’s connection to other systems and hardware components, alignment with corporate policy, government regulations, and so on

If you’re concerned about how to write specifications for mobile app development, start from eliciting your business requirements.

Business requirements

When writing your business requirements, focus on reasons why building a mobile application is essential for your business, the changes the app will entail, and the outcomes you expect it will deliver. To keep your product vision clear to your development company, you should record your business requirements in a mobile app business requirements document (BRD).

Note that although we use the term “document,” this doesn't have to be a printed piece of paper or a Google Doc. You can store your requirements using diagrams, databases, spreadsheets, or requirements management tools, or you can combine these with a traditional text document.

Based on the vision and scope document proposed by Karl Wiegers in the third edition of Software Requirements, we’ve prepared the following BRD structure:

1. Business requirements
Background	Describe the situation that led you to the idea of creating a mobile app, the overall goal(s) for your project, and improvements you suppose it will bring to your business.
Business opportunity	Highlight strengths and advantages of your app compared to existing solutions on the market. Describe how your mobile app will keep up with market trends and ever-evolving technologies.
Business objectives	Summarize what benefits you expect to get from building a mobile app in a quantitative and measurable way. Your objectives must be SMART (specific, measurable, achievable, relevant, and time-bound). An objective may read like this: “I want to bring in $X in revenue and return Y% on investment within Z months.”
Success metrics	Determine what indicators will help stakeholders understand that your project has achieved success. For example, for an e-commerce app, to bring in $X in revenue within Z months, a good goal could be getting two cross-sales on 80% of orders.
Vision statement	You can describe your product vision using the following format: For (target users) Who (need or want to change something) The (your product name) Is (a mobile app) That (will provide unique valuable functionality, key benefit) Unlike (current business model or competitors) My product (advantages that differentiate your app from competing apps)
Monetization model	From the outset of your project development, define how your mobile app will generate revenue. You can check out possible monetization models for mobile apps in our previous article.
Business risks	Think of possible situations that can adversely affect your mobile app development. For example, what will you do if you get too few downloads? You need primarily to estimate the probability of this risk and how it will impact the whole project. Then plan actions to control, mitigate, or eliminate the risk. Involve other stakeholders to join in the decision-making.
Assumptions and dependencies	Business assumptions reflect your observations of ways you can achieve desired business objectives. Given the objective to bring in $X in revenue within Z months, your assumption can be that a new app will attract 100 monthly active users who will spend on average $15 a month. Highlight external factors that your mobile app development depends on, such as third-party suppliers, partners, other business projects, industry standards, or legislation.

2. Scope and limitations
List of features	Define what features your app must, should, could, and won’t provide based on your business objectives, time and financial resources, and problems with existing business solutions, if any.
Scope of initial release	Define what features you should develop first. For help deciding, read our article about nine techniques to prioritize features for a mobile app.
Scope of subsequent releases	This section describes features that aren’t so critical to be developed first because of their complexity, high cost, or low profitability. You can implement them in future app releases.
Limitations and exclusions	List features that you have to cut from the project scope. You can add them to subsequent releases.

3. Business context
Key stakeholders	Create profiles of everyone somehow related to your project: those who take an active part in mobile app development, who depend on its outcome, and who impact its outcome. To get the ball rolling, you can start from your corporate organizational chart.
Project priorities	Agree on features, quality, schedule, budget, and team size. Prioritize the factors that lead to your project’s success and define constraints on project development. Discuss the degree of freedom you can grant your project manager to accomplish tasks that lead to project success within the existing constraints.
Deployment considerations	Describe possible improvements you want to make for your mobile application to expand its market share. These can be extra features to reach audiences in other countries or new cloud data storage to make your app more adaptive.

You can represent your project scope using different tools. The most comprehensive is a lean canvas. It represents the segments of a business plan crucial for developing documentation for all mobile applications: groups of users and their main problems, solutions your app is going to provide along with a unique value proposition (UVP), and other advantages. In the lean canvas model, you can describe the channels you’ll use to attract target users and key metrics that will tell you how your business is doing. A lean canvas also helps you determine the monetization model for your mobile app along with other potential revenue streams.

Dive deeper: How to make a business model canvas for a mobile app

To foster clear communication among all project stakeholders, at Mind Studios, we additionally use a mind map. This tool mirrors the logic of a mobile application and the interconnections between its main components.

Here’s a simple example of a mind map for a meditation app like Headspace:

Remember that drafting business requirements for mobile applications involves all project players. It is always a joint effort.

User requirements

After identifying your business requirements, it’s time to focus on your users’ needs. You need to outline potential aims with which users come to your app and the actions they will take to meet these aims. But whose opinion should you consider when drafting user requirements?

The trouble is, there’s no single type of app user. On the contrary, there are many types of users asking for different things: investors, business owners, end users, developers, distributors, regulators, marketing staff, and others. Your task is to hear everyone and find the balance between the needs of different user groups.

When it comes to user requirements, it’s sensible to start with these three steps:

Step 1 — Classify users. Group all stakeholders into user classes. You can sort them according to the following criteria for mobile applications:

• Access level (guest, regular user, paying user, provider, administrator)
• Tasks they perform (find, view, read, select, buy, share, comment)
• App features they use (searching, mapping, sorting, comparing, paying, etc.)
• Frequency of visits (daily, monthly)
• Platforms used (iOS or Android)
• Native language (or other demographics like location, gender, education, and family status.)

Step 2 — Identify product champions. Choose individuals who can represent each group of users and communicate user requirements to your project manager. Being a good product champion means having a clear vision of the benefits your app will bring to users. In turn, product champions must be actual users to perfectly understand users’ pains and urgent needs.

Step 3 — Agree on the requirements decision-makers for your project. Agree on representatives of each group of users with stakeholders. Be careful not to overlook any stakeholder to avoid complaints that the final app doesn’t meet a stakeholder’s expectations.

After identifying eligible user representatives, get their input on two types of user requirements to develop an app.

User requirements
Functional user requirements	Outline tasks users want to perform within your mobile app and list possible user–app interactions. Based on this data, you can derive the core functionality your app must provide to enable these interactions to happen.
Non-functional user requirements	Gather users’ expectations related to your mobile app’s level of performance, security, usability, and so forth.
Deployment considerations	Describe possible improvements you want to make for your mobile application to expand its market share. These can be extra features to reach audiences in other countries or new cloud data storage to make your app more adaptive.

Record feedback from users in a user requirements document (URD). To do this, you can use the following techniques:

A user persona is a useful tool that allows you to visualize your target users. For each user persona, choose a name and a photo, then list the user’s needs, wants, and aims. Write key reasons why the persona will use your app. Here is an example of a user persona we made for a social media app like LinkedIn:

User stories. Itemize actions users will perform within your app to meet their goals. Then arrange these actions in a natural sequence to determine a typical user journey through your app. Depending on your project’s scope, you can primarily outline epics — intricate user actions that you can decompose into smaller steps users will take while using your app. Epics are user stories that tend to be written as follows: As a <type of user>, I want <some goal> so that <some reason>.

In Agile development, user stories are often put into a product backlog. While negotiating the scope of software development for the first and subsequent releases, you and your development team will consider user stories from the backlog and select the most relevant. By arranging user stories, you can form a product roadmap that clearly defines what app features you should implement and when. The example below is related to the two most common basic epics for any mobile app:

System requirements

A complete product requirements document for a mobile app should contain requirements on how your app must operate. Resist the lure of hastily writing a technical design document for a mobile application based only on users’ wants and business needs. Talk to developers. They’ll give you feedback on whether it’s technically possible to realize your original plans for the app’s functionality. In talking to developers, you’ll reveal potential threats to your project development and can collectively establish a plan B to sidestep them.

After constructive dialogue with your team, write down the agreed requirements in a software requirements specification (SRS) for a mobile application that contains the following blocks:

System requirements
Functional requirements	List the features developers can build to enable users to complete tasks according to your business requirements. To do this, use existing mind maps or user stories. After defining what your app will do, assign a unique name and number to every functional requirement along with a short description, rationale, and status.
Subsystem requirements	Describe requirements for developing an app from the perspective of software and hardware subsystems. For example, if you’re going to build a fitness activity tracking app, you’ll need to write requirements for wearable trackers that will synchronize with the app.
Business rules	Since every business is subject to laws, policies, and industry standards, these will be obvious sources of requirements for an SRS. Here’s a shortlist of requirement sources: Corporate policy Government regulations Industry standards User roles and permission ratings If-then models of user behavior Computational algorithms, if any
Data requirements	When developing a mobile app, you need to create, store, modify, display, delete, process, and use massive amounts of data. To manage data flows, you need to: outline a logical model of data entity interactions define entities in the data dictionary specify how the system must enforce data analysis, retention, or disposal choose types of data reports (spreadsheets, charts, dashboards, etc.)
Quality attributes	Writing clear quality criteria ensures that developers will meet your expectations with the end product. You need to consider quality attributes that are important to: your business and users, such as usability, performance, and security (external attributes) developers, such as efficiency, modifiability, and portability (internal attributes) Discuss what attributes are critical to your app’s success with other stakeholders and prioritize them. Write specific expectations for each attribute using fit criteria — a quantification of the requirement that describes the standard your app must reach. Translate quality attributes into technical specifications and write acceptance tests for your team to enable them to check results.
External interfaces	This part of a functional requirements document for a mobile application is needed to ensure that your app will communicate properly with users and external hardware or software systems. In an SRS, you need to write down requirements for: User interfaces. Specify the design of your mobile app’s screens (standards for fonts, icons, color schemes, images, screen size, layout, resolution, and so forth) Software interfaces. Describe interactions between your app and other software components including other apps, websites, libraries, databases, and tools. Hardware interfaces. Outline each of the supported device types, data and control interactions between software and hardware, and communication protocols to be used. Communications interfaces. In an SRS for your mobile app, state requirements for any communications functions your app will use, including in-app messages, push notifications, emails, and network protocols.
Constraints	Record constraints that restrict your mobile app’s design, operation, and implementation. First of all, check whether your mobile app specification aligns with Apple App Store and Google Play Store requirements. Additionally, specify other system constraints imposed, for instance, by the programming language used or rules of using third-party APIs or content.
Localization requirements	If you want your app to be used in countries, cultures, and geographic locations that differ from those in which it was created, then you should set requirements for changing: Currency Date, number, address, and telephone number formats Language (including national spelling conventions, local dialects, directions) Functionality to comply with regulations and laws Content in consideration of cultural and political issues Time zones Weights and measures Other variables

Let’s take a closer look at the tools that are used for representing system requirements in a product and technical specification for apps.

Spreadsheets offer a traditional presentation in rows and columns of app functionality you intend to build. Let’s review a fragment of the functional requirements spreadsheet we drafted as part of a real estate mobile application development document:

An entity-relationship diagram (ERD) represents how data entities relate to each other within a system and connections between elements within those entities. The following is an example of a diagram we used in a requirement specification document for a food delivery mobile application:

Learn more about building a food delivery app like Postmates

Ways to develop and manage requirements

As your project evolves, changes to software requirements for app development are inevitable. New requirements can come from anywhere: Your investors can insist on getting a return on investment faster than you planned; users can go to a competitor’s app because your app doesn’t provide a feature they like; subsequent software updates can impose extra restrictions on your mobile app development.

It’s tempting to outline software requirements for mobile application development once and for all, but doing this can lead you to project failure. Let’s figure out why requirements development is an iterative process.

Drafting a document of requirements for your mobile app project is commonly about performing four activities:

1. Elicitation, or asking what users expect from a new product, listening to what they say, and watching what they do
2. Analysis, or processing user feedback to understand, classify, and relate this information to possible mobile app requirements
3. Specification gathering, which involves turning vague user input into thoughtful, structured, written requirements documents with visual illustrations
4. Validation, which is about drawing confirmation from stakeholders that the requirements specification you’ve created is accurate and complete

While conducting analysis, you can realize some inaccuracies that turn you back to elicitation. And while writing a mobile app product requirements document, you can bump into some gaps that require you to conduct more analysis. If stakeholders point out errors in your requirements document, you will have to rewrite some statements, conduct a re-analysis, or even conduct a follow-up poll. Only by interweaving and iterating these activities can you provide stakeholders with relevant mobile app requirements through the whole development cycle.

At Mind Studios, we define and agree upon initial product requirements at the discovery and idea validation stage by taking the following steps:

Elicitation	Define business requirements
	Identify stakeholder groups
	Select requirements decision-makers
	Analyze the target audience by conducting: focus groups interviews questionnaires workshops search queries social media analysis forums research
	Perform document analysis
	Examine problems with previous solutions
	Identify user requirements
Analysis	Conduct SWOT analysis of competitors
	Analyze idea feasibility
	Flesh out requirements
	Prioritize requirements
	Derive functional requirements
	Make sketches and mock-ups
	Create a glossary
Specifications	Adopt a requirements document template
	Record business rules
	Specify non-functional requirements
	Document requirements using diagrams, spreadsheets, and wireframes
Validation	Create prototypes
	Test requirements
	Correct requirements
	Define acceptance criteria

In the name of your project’s success, you need to rein in requirement volatility with sound management. A project manager and/or a business analyst can take on this responsibility. Project managers and business analysts have different requirements management tools to:

• Track the need for changing requirements
• Perform impact analysis to determine what these changes will bring to project development
• Trace requirements maintenance
• Track the status of each requirement
• Track requirements issues
• Maintain a history of requirements changes

Characteristics of a good mobile app development requirements document

Since nowhere more than in product requirements do the interests of all stakeholders intersect, you need to be sure your requirements are equally clear and understandable to investors, users, and developers. How to build a mobile app requirements document to meet everyone’s needs? Not only the contents of a web app requirements document but the tone of voice can help you with this.

Go above and beyond to get a high-quality product requirements document. Discuss the level of detail, representation techniques, and writing style that are best for stakeholders.

In a perfect world, your mobile app requirements stated in a PRD should be:

• Complete. For example, each functional requirement should contain enough information for developers to be able to implement it correctly. If you have some gaps, mark them as TBD (to be determined) and follow up on them later.
• Correct. You and your development team should both verify the correctness of your mobile app’s product requirements document. You can consider requirements correct if they conform to technical specifications, business rules, industry standards, and relevant laws.
• Consistent. This means no requirements in a PRD should contradict other requirements in the same PRD.
• Feasible. It must be possible to realize each product requirement within the operating environment on hand, given the known staff capabilities, time, and budget. The Agile development methodology and proof of concept prototypes help you evaluate requirement feasibility.
• Prioritized. Each requirement, be it a functional requirement or a user requirement, must be ranked for importance to be implemented for a particular release.
• Modifiable. Since requirements can change during development, your product requirements document structure needs to be flexible.
• Verifiable. Product requirements must be measurable and specific so that testers can check them with tests and determine whether a particular requirement is properly implemented.
• Unambiguous. One of the main reasons to write a mobile app product requirement document is to reduce miscommunication. You need to write every requirement so it can only be interpreted in one possible way.

We strongly recommend creating a glossary of terms from the outset of development. The fact is that developers aren’t familiar with your business speak, and probably you aren’t proficient in programming. A lack of understanding of terms can lead to rework, missed deadlines, cost overruns, and unnecessary debates.

A mobile app requirements document template

Some businesses demand a detailed list of requirements backed by a well-thought-out technical specification, while others are content with a shallow approach. No matter what group you belong to, you have to start somewhere.

As guidance to develop initial requirements, you can download our mobile application documentation sample in PDF. It provides enough core information to ease and accelerate a developers’ entry into your project and, therefore, to save you time and money.

Moreover, if you’re ready to cooperate with our team to develop your project, you can send us a filled-out PRD template via Google Forms.

Final word

Even for the smallest projects, it’s critical to have a shared understanding of initial requirements. In some cases, ready-made product requirements document templates can help you out. But more often, they’re only illustrative. Since no two apps are alike, there’s no chance that someone else’s PRD will suit your project.

To perfectly meet your specific tasks, you need to create an original mobile app requirements document, which can be a time-consuming and tedious process. The good news is that you can leave it to experts. Especially since they’re just one call away.

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