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 sample to help you get started.


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

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

Six reasons your mobile app needs a 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.

Writing a mobile app product requirements document (PRD) 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.

  • 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.

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 take developing requirements not as a wasteful and frustrating matter but as an investment in your project that will pay off in spades.

Types of requirements

Three main types of 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 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

Three main blocks of a business requirements document

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.

Lean model canvas template

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:

example of a mind map for a meditation app


Read more about how to make a meditation app like Headspace.

Remember that drafting business requirements 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:

  • 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.)

Read more about how to find the target audience for your mobile app.

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.

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:

example of a user persona

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:

most common basic epics for any mobile app

System requirements

Potential structure of a software requirements specification

A complete product requirements document for a mobile app should contain requirements on how your app must operate. Resist the lure of hastily writing system requirements 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) 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 your mobile 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 requirements 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 you can use for representing system requirements in your software requirements specification for a mobile app.
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:

part of a real estate mobile app development document


You might be interested in: How to make a real estate app like Zillow.

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:

diagram we used in requirement specification document

Learn more about building a food delivery app like Postmates

Ways to develop and manage requirements

develop and manage requirements

As your project evolves, changes to software requirements for your mobile application 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 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


Read more Mobile app development process for launching successful apps.

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

good-product-requirements

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 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 fill in our mobile app product requirements template. It provides enough core information to ease and accelerate a developers’ entry into your project and, therefore, to save you time and money.

Mobile app product requirements document brief made by Mind Studios

Introduction

Briefly outline what industry your business is in, the idea behind your mobile app (What made you think of building an app?), and how you expect the app will improve your business.

Business requirements

  1. Why did you decide to create a mobile app?

    • To share your unique experience
    • To create an extra revenue stream
    • To improve current business processes
    • To get a return on investment
    • Another reason
  2. What is the main purpose of your project?

    • To launch a new business, product, or service in a new market
    • To enhance brand awareness apart from the website
    • To make improvements to, redesign, or create a new version of the current app
    • Something else
  3. What category does your app belong to?

    • Gaming
    • Entertainment
    • E-commerce
    • Education
    • Lifestyle
    • Utility
    • Travel
    • Other
  4. What are your financial and nonfinancial business objectives?

    • Financial objectives: I want to capture an X% market share within Y months.
    • Nonfinancial objectives: I want to be rated as the top mobile app in its category in the Apple App Store and Google Play Store by a specific date.
  5. What do you expect your app will do?

    • Describe core functionality
    • Offer a unique value proposition
  6. Who are your direct and indirect competitors?

    • List three to five main competitors in your niche (along with links)
    • State features you like and dislike in your competitors’ products
  7. What is your product vision?

    • For (your target users) who (need to or want to change something), (name of your mobile app) is a mobile app that will provide (a killer feature). Unlike (current business model or competitors), my app will provide (main advantages).
  8. Choose your monetization model:

    • Paid advertising
    • In-app purchases
    • Freemium subscription
    • Premium subscription
    • Something else

User requirements

  1. Describe the user roles in your app:

    • Guest / regular user / paying user
    • Buyer / seller
    • Customer / executor
    • Student / teacher
    • Provider / administrator
    • Your classification
  2. Based on user roles, create up to three possible user personas considering the following criteria:

    • Demographics (age, gender, family status, education level, job type, location)
    • Psychographics (pain points, aims, needs, vital problems, attitudes, motivations, opinions)
    • In-market behavior (apps used, sorts of services/goods bought, reasons for using the app or buying the product or service, solvency)
  3. Determine your target users’ preferences in terms of:

    • Device type: smartphone, tablet, desktop, smartwatch, smart TV
    • Platform: iOS, Android, cross-platform
  4. Describe the user journey:

    • Sketch a typical path your users will take within your app to get desired results
    • Add links to sketches of possible app interfaces

System requirements

  1. Describe the features you want your app to provide users with:

    • List up to three must-have features
    • Add links, if any, to examples of how a particular feature needs to look
  2. What type of content would you like to add to your app?

    • Videos
    • Audio
    • Animations
    • Images
    • RSS feeds
    • Other
  3. What current services, servers, and databases do you use?

  4. What third-party applications, services, and databases do you need your app to be integrated with? (payment gateways, social media, etc.)

  5. What operating system versions should your app be compatible with?

  6. Describe your UI requirements:

    • Mobile app style
    • Color scheme
    • Logo
    • Icons
    • Buttons
    • Images
    • Fonts
    • Link to brand guidelines the team needs to follow
  7. Do you have current provisioning profiles in the Apple App Store and/or Google Play Store?

  8. What hardware does your app need to synchronize with? (wearable devices, drones, etc.)

  9. Describe your app’s quality criteria regarding:

    • Usability
    • Performance
    • Security
    • Safety
    • Other quality attributes
  10. What languages should your app be translated into?

Other requirements

  1. What are the constraints and limitations within which the team must work?

    • Business rules
    • Industry standards
    • Government legislation
    • Other possible constraints
  2. What is your project timeline and budget?

    • When do you expect to start and finish the project?
    • What is the approximate budget (USD) you can allocate to the project?
  3. What services would you like to request from your software development team?

    • Full-cycle mobile app development
    • Website development
    • Continued support and maintenance
    • Promotion and marketing
    • Interface design
    • IT consulting
    • Additional services

After you complete this brief, email it to us and one of our managers will respond promptly. This brief will provide a solid basis for creating a detailed mobile app product requirements document with the help of our team.

Have any questions about your mobile app project? Drop us a line.

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.