A Complete Guide to Software Requirement Specification

At Space-O, we have delivered over 300 custom software solutions.

And, during this software development process, we need to make sure of these points:

1. Validating software idea and its scope
2. Giving detailed and proper estimates to the client
3. Design and development on time
4. Final deployment on a fixed date

That’s a long process.
There is no scope for mistakes.

Then, how do we manage to deliver these custom software on time?

The answer is clear and detailed software requirement specifications (also known as an SRS). Yes, being a leading software development services provider firm, we make sure that we spend our time and assign the best resources to create an SRS document.

In this guide, we are planning to share all our experience with software requirement specifications, and everything around it.

By the end of this blog post, you will learn

• What is an SRS document?
• Why Create an SRS document?
• What is the Structure of an SRS document?
• What are the functional requirements in SRS?
• What are non-functional requirements in SRS?

Let’s get started.

What is a Software Requirement Specification?

Software requirements specification is a document consisting of essential information on software development.

An SRS document has these two pieces of information.

• What is the purpose of your software or what your software will do
• How your software will be likely to perform when used by end-users

This document also describes the functionalities needed in software for users. In short, an SRS document is a roadmap to the development of your software.

Why Create a Software Requirements Specifications Document?

Here are 4 reasons for creating an SRS document.

• An SRS document works as a written agreement between you and your development company
• An SRS document eliminates the misunderstanding between all team members
• An SRS document helps you to be on the same page with the developers that you have hired
• An SRS document includes the technical details about the software and it saves the time of developers

Let’s move to understand the structure of an SRS document.

What Does an SRS Document Include?

In the software development process, the SRS document is the most essential part.

An SRS document contains these requirements:

• Includes the problems that need to be resolved with the help of the software
• Describes the overall information of the project
• Contains the functional requirements of the software
• Contains the non-functional requirements of the software
• Includes the Flowchart of the software
• Includes the design constraints of the software
• Details on how the software will interact with other software or hardware

What is the Structure of a Software Requirement Specifications Document?

Here is the general structure approved by IEEE to follow for creating an SRS document.

What if an SRS Document is Not Written Before Development?

If you don’t create an SRS document, then these are the problems you might face.

• Without an SRS document, developers don’t get clear requirements, which results in an increase in development time.
• There will be no base to validate the software against the end-users requirements.
• If an SRS document is not created, there is no base of cost of software development and tentative delivery timeline of the software.

How to Create an SRS Document from Scratch in 4 Steps

As an entrepreneur when you outsource software development, you must know the basic steps that Business Analyst follows to create an SRS document. If you know these four simple steps, you would be easily able to cross-question where required. Here is the general process that the BA team follows to create an SRS document.

1. Define the Purpose of Your Document

Write a detailed introduction of your software project. You need to write what your software project is about, the features of your software, the interfaces of the software, what the software will do, and how the software will interact with external resources. When the project owner or stakeholders or developers check your SRS document, it allows knowing the expectations and how the software will work.

2. Define the Scope of the Project

An SRS document cannot be built on the basis of assumptions. So, before writing any feature or functionality in the SRS document, you need to be very sure about it. For ensuring clarity, you need to know what end-users will achieve with your project.

This clarity often originates from a well-constructed work-break structure (WBS) which helps to break down the project into small and manageable components and helps to identify all the necessary features and functionalities.

Read this complete blog post on the work-break structure to get an in-depth understanding which helps you to create a clear SRS document.

An SRS allows you to define the scope of your project. A clear picture of the user journey helps to know how the software will be useful, which problem it will solve, and which features will be suitable for the end-users.

In short, you need to describe the business goal of your project. So, developers create your software according to your requirements and by following the latest trends in software development.

3. Define the Functional and Non-functional Requirements

In this stage, you need to be more specific about the requirements of the software. You need to describe the information of functionalities in detail. Because this part of an SRS document is the most core and essential component.

Herein, you need to write your project’s functional and non-functional requirements. While writing on the functional requirements of the software, make sure you meet the user’s needs.

Describing the functional requirements of your project helps your developers to get a complete overview of the project development. Functional requirements help developers to get started on the rapid application development of the project without spending time researching and looking for the requirements.

In addition, you need to mention the use cases of each stage in the software. This way, it helps you to measure the progress of your project development. To make your SRS document accurate and more specific for your developers, add details like glossaries of terms, references, and appendixes.

4. Get Approval for Your Written SRS Document

Once you have written or described all the information about your project, it’s time to take the approval of the SRS document from your client or stakeholders.

While sending your SRS document to your client or stakeholders, you need to give them a small explanation about this document. Once they read your written SRS document, they might ask for changes or you get feedback on it.

Implementing the changes will help you to make the document precise for the overall development of the project. So, while developing the complete solution, your developers don’t get off track.

Moving further, let’s understand the functional requirements.

What are the Functional Requirements in an SRS Document?

Functional requirements are related to the functionality or features of the software.

You need to describe the functionality that will be in the software. These functional requirements will allow your system to perform the function as intended. When any input is given in the software, then what a system must do and how the system must work.

In short, it includes all the features of the software that are included in the software based on the user’s needs.

Here’s an example of functional requirements.

Suppose, a user downloads and install software, then the user use the software in an efficient way.

Functional Requirement Examples:

1. Sign-up or Register page
2. Normal login or social media login
3. Phone number verification
4. Forget password “this section helps users to reset passwords if forgotten”

So, the features of the software represent the functional requirements of a software system.

What are the Non-functional Requirements in an SRS Document?

Nonfunctional requirements are about describing the several attributes of software like security, performance, scalability, maintainability, and usability.

Nonfunctional requirements are also known as NFRs.

Here’s the list of aspects to test the non-functional requirements of the developed software.

• Performance of your software in normal scenarios
• Behaviour of your software when there is a sudden increase of users
• Functioning of your software when operating on minimum resources of hardware
• Scalability of your software
• Performance of your software OS to OS or device to device
• Security of your software

What are the Best Practices to Follow While Writing an SRS Document?

Follow these five best practices to write a system requirements specification document.

• Have a clear vision of the project and clarity of the requirements
• Write an SRS document in a layman’s language so it becomes easy to read and understand
• Your SRS document must not have any assumptions because it may mismatch the core requirements when developed
• Include the tech stack information for the software development

Which are the Different Tools Available to Create an SRS Document?

To create an SRS document, you need the right tool that helps you write an SRS document without any hassle. To help you choose the right tool, here are the two most useful tools in writing an SRS document. Generally, most BAs use these two tools to write an SRS document.

• Google Docs
• MS Word

What are the Qualities of a Good SRS Document?

Here are four qualities that make an SRS document up to the mark.

• Concise – Your SRS document should have to-the-point information and also be unambiguous, consistent, and complete with all required data.
• Structured – It should be well-structured because formatting helps to easily understand the details included. As the SRS document goes into revision, you need to ensure that making modifications is easy.
• Black-box view – An SRS document should include the external behaviour of the system and what a system should do. So, the document should be prepared as a black box.
• Verified Information – All the information included in the SRS document should be verifiable when developed. So, it allows you to verify in the later development stage whether the requirements are implemented as described in an SRS document or not.

How Does an SRS Document Help Developers?

An SRS document provides a complete overview of the entire project. So, developers do not need to start from scratch including research, deciding features/functionalities, and completing the path of development. In addition, developers are able to choose the right one from different available software development methodologies.

An SRS document works as a base for the entire software development team. This way, you ensure that every individual in the development team is aware of their responsibilities and accomplishes them well.

How SRS Documents be Helpful to Clients?

An SRS document offers a clear picture of the project to the clients. A software development specification document works as an agreement between clients and organizations. An SRS document is a bridge between a client and developers. So, it becomes for clients to validate and verify the requirements when the software gets developed.

What is the Process Space-O Follows to Write an SRS Document?

To create an SRS document for our client, we follow these 8 simple steps that help us to write a detailed system requirements document.

• Our BA takes a call with a client and completely understands the requirements
• Once the wireframe of the software gets finalized, then our BA starts working on the SRS document
• First, our BA defines the outline of the software, then describes the purpose and scope of document
• After that, our BA determines the project definition that covers attributes like objective, target groups, system platform, app orientation, language, offline support and essential links.
• The next section in the document describes the strategy for completing the project development. We even show the working flow to our clients to make it easy for the client to understand.
• After describing the strategy, we describe the software development tools and technologies.
• Then, the flow of the software gets described with a diagram that makes easy for the client to understand
• After flow, our BA explains each screen image with details like introduction, its precondition, and working logic. (This is done for every screen of the software)

Let’s understand the benefits of creating an SRS document.

What Are the Benefits of an SRS Document?

Here are the benefits of an SRS document for the client and for the developers.

Summary of Creating an SRS Document

Creating an SRS document is time-consuming and requires close attention to the details.

If you want to create a custom software solution for your business, and want to start with proper planning, and a proper and detailed SRP document, let’s get in touch.

As we have developed over 300+ business solutions, we know how to make a proper SRS document from scratch.

If you want to see the SRS documents that we have created, please drop us a message as well. That way, you will get more clarity about the details we consider in the SRS document.