Software Requirement Specification: How to make SRS for your project [with examples]

When delivering a top-notch software solution, any IT company should rivet attention on creating a detailed software requirements document (SRS) that forms the basis for development, design and management activities. Therefore, the mentioned document is like a single source of truth for any persons engaged that assures they are on the same page. That’s why defining project requirements before starting the development process will save time and money. What’s more, if they are clearly defined, it definitely bears great fruit for your business.

It’s no secret that each IT company or tech partner always provide their unique approach to preparing documentation. Fortunately, here we explain the paramount importance of writing SRS documentation for any project - web or mobile and share our best instructional guidelines on how to write a practical and useful SRS to prevent some issues your team may come across. Let’s jump right in!

What’s SRS?

Typically, it’s a document including a purpose, overall description of the project and specific requirements; describing the probable system capabilities that will meet the various customer’s wants and needs; taking into account how the future system will function and accomplish users’ goals, etc.

It’s true that "software requirements specification"&"system requirements specification" are used interchangeably as the acronym "SRS." Aren’t you confused when hearing this acronym? Doesn’t it disorientate you? Do you know the difference between them? Let’s define:

• A software requirements specification (SRS) includes in-depth descriptions of the system/software developed while a system requirements specification or SyRS just collects information regarding the system/software requirements. Let’s dig a little deeper!

What Does an SRS Include?

The classic SRS document:

• describes the purpose of the project,
• describes the features of the software to be developed
• lists the software requirements in detail.

The SRS document contains both general and detailed requirements for the software to be developed. In addition to the requirements, the SRS document provides a set of use cases that clearly explain how the user is expected to interact with the software.

Let's take a closer look at what an SRS document consists of:

• The reasons why the customer initiated the development of the system;
• Problems associated with the existing system and how they can be solved by the system being developed;
• The customer's business ecosystem (business model, business operations, organizational structure, etc.) that the system must serve;
• Functional requirements. This describes the specific functions and capabilities of the software, as well as use cases, anticipated user actions, and the system's response to the interaction.
• Non-functional requirements that define how the system should work rather than what it should do. This includes quality aspects such as performance, reliability, usability, safety, and other quality attributes.
• Constraints and restrictions, including security, hardware limitations, standards compliance, reliability and fault tolerance, and the development team's assumptions about what is expected to happen during the project.
• Acceptance criteria, that is, the conditions that the finished software must meet to be accepted by the customer.

What Are the Goals of SRS Documentation?

Here we have identified some priority goals that a well-written SRS should achieve:

• Deliver feedback to the client/customer and make sure that the IT company or tech partner understands what issues the software/system should solve and how to address those issues.
• Help to break down the problem into smaller components by merely writing down the requirements.
• Keep vital aspects that help to understand project deeply and deliver design solutions accordingly.
• Speed up the testing and validation processes.

Also, you will definitely ask ‘who are the SRS users?’. If a technical writer (TW) writes the SRS documentation for the future product, it is critical to mention that many other people can be involved in planning and preparing the SRS documentation. They are business analysts (BAs), project managers (PMs), software engineers, QA/QC engineers, customers, investors, etc.

Who Should Be Involved in Writing an SRS Document?

SRS documents are usually written by subject-matter experts as well as business analysts and project managers. They communicate with the customer and all stakeholders, gather requirements, conduct user research, and then translate the collected disparate data into a structured, and easy to understand roadmap for all involved.

However, situations vary, so it makes sense to provide a complete list of those who may be involved in creating an SRS document.

• Business Analysts: They gather and translate business needs into requirements for the engineering team.
• Product Managers: Align software with market requirements, ensuring it meets user expectations and business goals.
• Subject-Matter Experts (SMEs): Depending on the industry, these can be experts in medicine, finance, education, etc. They make sure that the software meets industry standards and requirements.
• Software Architects: Their job is to design the overall software structure and define how the different components should work together.
• Engineers: They build software according to the SRS document.
• UI/UX designers: Their job is to create the user interface, ensuring that it is user-friendly and meets user needs.
• Quality Assurance (QA) Engineers: These professionals test the software against requirements, finding and fixing bugs and problems.
• Customers/Stakeholders: Provide feedback, thereby signaling that SRS accurately reflects their needs and expectations.
• Document Author: He or she documents the requirements, ensuring that they are clear, structured and easy-to-understand for all involved in the process.

Your SRS document development team may consist of all of the participants listed above, or you may bring in other experts.

What Techniques Do You Apply to Create an SRS Document?

In today’s business world, you should apply proven ways to identify the client’s wants and needs. Some techniques may be highly beneficial in one project but may not be as productive in the other one or for some tech providers. Here we provide some vital requirement gathering techniques you can utilize. Let’s take a closer look below:

• Brainstorming. Helps to identify all possible solutions to challenges. Any ideas are welcomed, and all participants are encouraged to develop a rich array of creative solutions.
• Document Analysis. Applied to identify the requirements by analyzing the existing documents - business plans, contractual agreements, logical data models and current process flows before organizing or scheduling an interview with stakeholders.
• Interface Analysis. Includes the user interface, interfaces with external applications and interfaces with external hardware devices to determine the boundaries and identify future functionality/features.
• Interview. Utilized to communicate with persons engaged or subject matter experts to gather requirements for the future project. The questions should be prepared beforehand or asked spontaneously; responses should be recorded or written down as well.
• Prototyping. Applied to build an initial version of the solution that may not have all the functionality but serves as a proof of concept for idea verification/further analysis.
• Mind Mapping. Represents ideas and their branches hierarchically, and helps to visualize the relationship among all components of the system.
• Focus Group. Involves synergistic discussion among people who are representative of the users or customers regarding to the functionality, features and other aspects of the product/system. You should collect feedback about opportunities, key features, needs, and so on to define the requirements or to validate the already elicited ones.
• Requirements Workshop. Brings a larger group on a common platform to discuss and reach agreements by defining cross-functional requirements for the future product/system in a fast way.

How to Write a Well-organized SRS Document for a Project Successfully

Below we have provided a step-by-step guide that helps you deliver a successful SRS document for your project, minimizes risks and speeds up the development process. Are you ready to delve into details? Then let’s start!

#1: Create an outline

Creating an outline is a significant step to take while writing SRS documentation. It allows you to invent new ideas collectively and make sure your document is organized and focused. You can use the sample outline provided below to create a professional looking SRS document for your project whether it is web or mobile.

#2: Define the project goal

Firstly, you should start by fielding questions like:

• What is the future product built for?
• What value does it deliver?
• Who are the rivals? How to outperform them?
• What are the basic requirements for the future digital solution?

Mentioned above questions help you identify and describe the goal. Also, you should define who in your company will use and have access to the product documentation, how they will handle it. This may include software and QA/QC engineers, business analysts (BAs), project managers (PMs) as well as customers, persons involved from other departments, including team leads, sales or marketing teams.

#3: Detail the requirements for the future product

Did you know there are many different types of software requirements? You definitely did! Here we present the requirement types - high-level and low-level that you should bear in mind. The high-level requirements are the following:

• business requirements that involve business mission as a whole;
• user requirements that identify how the users will interact with the system, how they need the product/system to function;
• system requirements that divide into functional and non-functional ones.

Stakeholder requirements, UI requirements (UIR), market requirements (MR), and so on are the lower-level types of requirements. Surely enough, any robust project should have balanced requirements that can be understood easily, written down or presented visually. Now let’s take a closer look at the system requirements:

Functional requirements

Functional requirements or FR for short are the ‘objectives’ of the software solution/system being built. They describe what future software/system should do and define how it will function to accomplish users’ goals. Below we have presented the best ways of documenting requirements:

User story

User stories are components of larger structures such as epics and initiatives. As a system requirement, it focuses on the point of view of the role that will use or be impacted by the solution. Also, it is helpful when avoiding common issues and pitfalls.

Herewith, we should mention that the acceptance criteria for a user story are essential to define the boundaries and parameters of a User Story and determine when a story is completed and works as expected.

Here is an example: User story and its acceptance criteria

The acceptance criteria for this story could be the following:

• Display statement balance upon authentication. For example, $1400.
• Display Total balance. For example, $3700 that includes the balance due from the current period $3000 and past balance due $700.
• Show Payment due date. For example, May 19th of the current month.
• Show Minimum payment due. For example, $140.
• Show an error message if the service is not responding or time is out. For instance, “Sorry, something went wrong with the service. Please try again later.”

Use case diagram

With a set of special-purpose symbols, it sums up the details of the system's users (also known as actors) and their interactions with the system. So let’s get to it:

• Actors are users that interact with a system/application.
• Goals show the end result of most use cases.
• System shows the interactions between actors (users) and the system itself.

Effective use case diagram describes the activities and variants used to reach the goal and helps your team discuss and display a wide range of scenarios of how the system interacts with organizations/people/external systems when achieving the goals.

Work Breakdown Structure or WBS

It defines all the things a software solution needs to accomplish, organized into multiple levels and displayed graphically. Its main idea is to divide complex activities into smaller, more measurable components. It aims to make large project parts more manageable. Breaking it down into smaller chunks means work can be done simultaneously by different team members, leading to better team productivity and easier project management in general.

Visual or design documentation

Undoubtedly, it is difficult to imagine how a new system will look and behave from reading a textual requirements spec. There are three ways to visualize textual requirements: wireframes, mockups, and prototypes. You think wireframe, prototype and mockup are all the same? Absolutely no. Let us show you why not!

• Wireframes are schematic pages used as a visual guide that shows the pilot system framework. They aim to represent functionality without displaying visual elements.
• Mockups reflect the design choices for color schemes, layouts, typography, iconography, the visuals of navigation, and the overall system design solutions; are static and unclickable.
• Prototypes are clickable system representations that display how users can interact with the system in a real world; enable designers to test users journey and find potential issues throughout the interaction flow.

With wireframes, mockups and prototypes, you can turn textual requirements into real representations, visualize, interact with various elements and solicit feedback.

Non-Functional Requirements or NFR

Being an extension to the functional requirements, these set of requirements help to describe how the system/software functions. Let’s find out what attributes used:

• Usability. Refers to the ease of accessing and/or utilizing the system to effectively and efficiently achieve the required goals.
  Example: The system must be user-friendly.
• Availability. Means that a system is fully operational and functions well when it's needed.
  Example: The system must meet the agreed availability targets 24/7/365.
• Scalability. Describes the ability of the system to perform under increased demand.
  Example: The system shall be designed, to support 1500+ users simultaneously.
• Performance. Refers to the system responsiveness when various type of users are interacting with the system/software.
  Example: The web page load time must be less than 1.5 seconds.
• Reliability. Describes the ability of a system to function under stated conditions for a specified timeframe.
  Example: The system database must be backed up after every significant update.
• Security. Focuses on data protection and prevent unauthorized access.
  Example: The system shall resist unauthorized, accidental or unintended usage and provide access only to legitimate users.

#4: Get approval for the SRS document

No sooner have you completed the SRS, you’ll need to have one last hurdle to clear: getting official approval from your key persons involved. This document is what will keep them interested and engaged in the future system and make them want to find out more. No matter how complicated an SRS is, you should explain to stakeholders what benefits it will bring to their business and encourage them.They should review the latest version of the SRS, may also ask questions to learn more and approve it as well.

Top 5 Challenges You May Face When Writing SRS for Your Web or Mobile Solution

Below you can reveal some common challenges you may face when writing SRS for your project and solutions to overcome them. Let’s delve into details!

Challenge #1: You have no idea how to define requirements for SRS

Solution to challenge #1: You can read the requirement eliciting techniques described above. Starting from brainstorming to a synergistic discussing, you will definitely understand the client’s wants and needs, then produce the requirements based on the information collected. In our article, you can find a step-by-step guide that provides some details on SRS document writing.

Moreover, here you can discover SRS sample or template that will help to accelerate the process of SRS writing.

Challenge #2: You have some difficulties when structuring or formatting an SRS for your web or mobile solution

Solution to challenge #2: With SRS sample, you can organize and structure the information elicited from the client hierarchically. If you only have an SRS sample and do not know how to deal with it or proceed, our team is always ready to give you a hand in writing a comprehensive SRS for your software solution.

Challenge #3: Are you fearful to write too many details?

Solution to challenge #3: One of the cornerstones of powerful SRS writing is the use of concrete details that can make the document clear and concise. The underlying concept is to deliver documentation with more quality details to help software engineers, QA/QC engineers, designers, PMs, stakeholders, investors, etc. instead of confusing them. Believe it or not, you should write as if the reader lacks knowledge in this area. That’s why you should write as simple as you can.

Challenge #4: You need to simplify the text

Solution to challenge #4: Language standardization of SRS is such a tedious activity. You should create a documentation style guide that everyone can follow whenever they need to document a new flow or process. Here you can find some simple rules to follow:

• Try to define terms before applying in order to avoid misapprehension. Also, eliminate jargons and words or word-combinations with multiple meanings that can be liable to misconstruction.
• Don’t forget to use phrases like ‘as indicated by’ or ‘according to,’ if you need to make references to illustrations/tables/charts/diagrams.
• Also, eliminate passive voice by making the subject do the action to soften the voice, keep to a minimum the weak phrases and replace them by picking the familiar or commonly used words over the unusual or obscure ones.
• Use the verbs ‘may’ or ‘should’ to tell about optional requirements while the verb 'shall' to describe 100% functional capability.
• Avoid using slash symbols. What does a “/” sign really mean? Is it and, or, one of, or a combination thereof (and/or)? These symbols can make all the difference between a clearly defined requirement and one that is impossible to interpret.

Challenge #5: Do you hesitate whether to check SRS or not?

Solution to challenge #5: Undoubtedly, you should proof your SRS document for grammar, spelling, fluency, punctuation, etc. errors. Yet, many documentation requirements make it to the verification stage without undergoing any prior quality checks for clarity, and consistency. In our article, we have provided a list of SRS document characteristics that help streamline the process of making sure the document prepared is well-written, clear and concise.

Integrating AI to Write SRS Documents

While developers are focused on the content of the SRS document, AI is engaged in writing it. Involving AI in writing technical documentation can significantly save valuable specialists' time, avoid repetitions and inconsistencies, extract hard-to-find data, structure it in a flash, etc. This can be facilitated by GPT-3/GPT-4, NLP-based requirements prioritization, semantic analysis of requirements, and other AI-based technologies.

Below are some key points on integrating Artificial Intelligence into SRS document writing:

• Automated requirements extraction. Instead of your PM, Artificial Intelligence can now extract requirements from various sources such as project documents, emails or conversations.
• Natural Language Processing (NLP). AI-based NLP helps to understand and interpret complex language. For example, it can be used to translate user feedback or requirements into structured SRS documentation.
• Requirements summarization. You no longer need to waste the time of your most valuable experts. Artificial Intelligence algorithms can summarize long and hard-to-understand statements into short and easy-to-grasp sentences.
• Automated SRS generation. No extra effort. Artificial Intelligence will now generate draft SRS documents based on the data provided.
• Error detection and correction. Unlike humans, AI does not get tired and even after a full day of active work, it detects hard-to-see errors, inconsistencies, or missing elements in SRS.
• Automatic updates. AI-based systems automatically update the document to reflect the latest requirements and changes.
• Version control. AI can track and match document versions, identifying differences or merging document releases.
• Chatbots to clarify requirements. Chatbots can clarify to stakeholders any ambiguities related to SRS requirements, thus helping all stakeholders to stay on the same page.

Characteristics of a Well-Prepared and Well-Thought out SRS

Are you interested? Let’s delve into details below:

• Correctness. SRS guarantees that the future system caters to the defined needs. That's why make the document as correct as possible from the very beginning.
• Unambiguity. SRS is the only interpretation of the future software solution usage and it is written in an easy-to-understand language.
• Ranking. Each requirement in SRS has an identifier to indicate either the importance or stability of that particular requirement.
• Verifiability. SRS utilizes measurable elements and defines terminology to avoid ambiguity.
• Modifiability. SRS is well-organized, any changes to the requirements can be made easily.
• Traceability. Each requirement in SRS can be uniquely identified in the original source (user stories, use cases, etc.).
• Completeness. SRS is a representation of all requirements for functionality, performance, features, design, etc.
• Consistency. No set of individual requirements in SRS conflicts with each other.

Benefits of a Great SRS for a Web or Mobile Project

The SRS provides scope for the team collaboration and accelerates the processes like development, testing, design and management. Sounds impressive, right? Let us show you why you will benefit by having an SRS in place for your future digital solution:

• Estimates costs precisely, increases the timekeeping accuracy.
• Accelerates and simplifies the “development-production” process.
• Extremely vital in the risk mitigation process.
• Provides details for future reference, delivers documented list of requirements to users.
• Being a single source of truth, it assures that all the persons engaged are on the same page and actually use the same document when taking decisions.
• Improves collaboration with stakeholders and a dev team by sharing the SRS document.
• Reduces task and subtask duplications, minimizes costly late-stage changes, shortens development efforts.

Who Needs a Software Requirements Specification and Why?

This is a very good question. The fact is that the Software Requirements Specification (SRS) document is required by everyone involved in the creation of the project - from the customer to the project manager in the IT outsourcing software development team.

Here's who uses SRS and why:

• The customer and all stakeholders use SRS to track whether the software being developed is aligned with the products and business goals they have in mind.
• Developers leverage SRS to understand what needs to be created, what functionality and specifications the software should have, what the product requirements are, etc. to meet the customer's expectations.
• Project Managers rely on SRS to define project scope, estimate costs, set and track timelines, and effectively manage resources.
• Designers utilize the SRS document when designing a software user interface to meet specified requirements.
• QA teams use SRS to define test cases, ensure software quality, and validate software compliance.

As you may have seen, all stakeholders, from developers to customers, use a Software Requirements Specification (SRS). This document helps them to stay on track and get the product they expect.

Bottom line: Are You Well-versed in Writing an SRS for Your Project Now?

Believe it or not, an SRS document is here to start if you are aiming to develop a software solution to flourish your business. That’s why a top-quality, well-designed, and well-written SRS document is crucial for the success of your future digital solution - web or mobile. Unfortunately, writing an SRS document is a challenging and tiresome activity. Having that in mind, you should dive deep into the ends and outs to elicit and figure out all the client's requirements, and share them with the persons involved to make sure everybody is on the same page.

Hopefully, our article covers step-by-step guidance on how to write a thorough and comprehensive SRS for a web or mobile project with examples. Anyway, we, at DDI Development, will help you get started, build and deliver a wide range of meaningful and robust digital products that fulfill your business mission and boost revenue.