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Best Guide on Software Requirements Specification 2024

Written By Zainab Aftab – Last Modified On April 19, 2024

How do clients and software developers connect to the idea of developing software? If the client is describing the software with a conceptual perspective and the developer is examining it with the complexity that goes behind developing it, How will you get them to see the same picture?

For this purpose, a software requirements specification (SRS) document is made. A good Software Requirements Specification document is a must-have and will help you manage your system’s complexity. This blog will deal with the purpose of writing a good quality Software Requirements Specification and how to write it.

What Is the Software Requirement Specification?

Software Requirements Specification (SRS) is a document that contains a detailed description of the programming codes, functions, what the user will be able to do after installing the code, and other necessary details about the software. It is written by a software developer, programmer, technical writer, or systems architect.

It works as an arrangement among the clients and software developers on how the final product will be designed. It also gives a reasonable estimate of the software costs incurred during the development process and programming necessities which make successful software.

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What Is the Purpose of SRS?

SRS document is built to get a clear picture of the software about to be made. It helps each member of the team to follow a single source. It includes all the necessary information from development to maintenance in one document. Besides this, it also helps avoid misunderstandings in the interpretation of software requirements between the development team and the contractors.

SRS is like your implementation plan, which is why it is crucial to make it before designing software. This document reveals the potential problems which the development team could face during the software development life cycle (SDLC). To sum up, SRS is a detailed description without which you cannot develop quality software. It is a software guide, and you must make one for any software.

Components of the SRS Document

A Software Requirements Specification (SRS) must have detailed the following components. Without these components, software developers cannot know the actual idea for the software in the mind of their customers.

  • Purpose of the Software
  • Description of the Software
  • Functionality
  • Non-Functional Requirements
  • Functional Requirements
  • Interface design
  • Limitations
  • Software Development costs
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6 Easy Steps to Write a Software Requirement Specification (SRS) Document

Writing an SRS document is not an easy process. It requires a team to reiterate the software’s idea and list the specifications. If a third party or technical writer is writing your software requirements specification, you have to define all the components of your SRS to them concisely.

We have prepared a list of steps you can follow while writing your SRS document.

  1. Create an outline
  2. Define the software’s purpose
  3. Overview
  4. Describe the needs
  5. Detail the types of requirements
  6. Get it Approved

1- Create an Outline

Your first step is to create an outline for your SRS document. You can use an existing template or the team can create it themselves. The outline should include three main things:

  1. Introduction
  2. Software Description
  3. Software Requirements

You have to further make categories in each of these three main headings. The introduction should involve headings of Purpose, Scope, definition, and Intended use.

2- Define the Software’s Purpose

Your second step is to define the purpose of your software briefly. This step sets expectations for your software. You will also describe the intended audience in this step.

Definition

In this section, you will define particular terms associated with the software. You will also define acronyms used in the document. It also involves identifying the severity of the risks involved in the project.

Identify the Intended Audience

This part will address the team allocation. Who is going to be responsible for what tasks? What are the key stakeholders? Who will have access to SRS?

Scope of the Software

In the scope of the software part, you simply define the problem your software will solve for its users, the benefits it will provide, and the goals and objectives of your company with the product.

3- Overview

In the overview section, give a brief description of how the software will work. What features will be included in the software? And also describe the functionality of your software.

4- Describe the Needs

Then comes the most interesting and important part. In this section, you have to give complete and concise details of the software you want to build. Describe who will be the users of your products. In other words, describe who is your target audience. How users will use your product? How will the interface of your product look?

You also have to address the needs of the user in this part. Like how they would react to your software’s interface. What features they will need to use it properly etc.

5- Detail the Types of Requirements

Your next crucial step is to write in detail all the requirements associated with your software. For your software development team to understand it properly, you must describe these details adequately.

Requirements for software include:

  • Functional requirements
  • Non-Functional requirements
  • Interface Requirements

6- Get it Approved

Now after you have dealt with all the steps mentioned above, it’s time to review the whole document and check it out for potential errors. You need to get the stakeholders’ approval and help everyone understand the SRS document. After that, you are ready to move toward the software building process.

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Types of Software Requirements in SRS

There are different types of software requirements that an SRS document must adhere to while listing the needs of the software.

Functional Requirements

Functional requirements in an SRS document define the system and the functionality of its components. These requirements briefly define the features of the software and the function of each feature. These are written while keeping in mind the demands and expectations of the end user from the software. They are analyzed in functional testing or API testing in the SDLC.

Non-Functional Requirements

These are the requirements that refer to the quality constraints of the software. It considers the various factors that should be incorporated into the software for its success—security, maintenance, Reliability, etc.

External Interface Requirements

This type of requirement includes the User Interface (UI) requirement for the software. It includes details of the screen layout, logic interface of the software, hardware interface, design, and other external interface requirements. Front and backend stack management is also included in these requirements.

What Is the Difference Between Functional and Non-functional Requirements?

Functional requirements of the software are a detailed description of how the software will work, its features, design, etc. In contrast, non-functional requirements deal with how the user will interact with the software’s interface. Non-functional requirements include user needs, expectations, software reliability, security, and usability.

10 Characteristics of a Good Software Requirements Specification (SRS)

  • Clear & Concise
  • Executable
  • Non-ambiguous
  • Ranked Requirements
  • Customizable
  • Easy to read
  • Completely Detailed
  • Consistent
  • Verification
  • Traceable

1- Clear & Concise

Clarity is very important while writing any business document. An SRS document requires the same, clear, and concisely defined clauses. Each line should have a single interpretation that is easily understandable by the audience. Writers must evaluate that it fulfills all the standards of clarity.

2- Executable

As we said, an SRS document is like an implementation plan, hence it is important that the schedule and costs mentioned in it lead to an executable plan. Writers must carefully plan the details of the execution of each step while writing the software requirements. The whole team should agree on the finalized description.

3- Non-ambiguous

Ambiguity cannot be allowed in a good SRS document as it can lead to disastrous results if any developer misinterprets the important parts. Reviews, ER diagrams, charts, and team checks are some methods to abstain from any ambiguity in the document.

4- Ranked Requirements

Requirements should be ranked in order of usability and significance. A criterion should be set to account for the most important requirements and the ones which have to be fulfilled first. Charts and diagrams could help to better decide the drinkability of requirements.

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5- Customizable

Modifications of the system should be kept into account while writing the SRS document. It should be made flexible to any further customizations that a team might decide to add later.

6- Easy to read

The readability of an SRS document is also imperative. Any acronyms used in the document must be defined in the introduction. Although the developers can understand any technical terms, any jargon that might confuse them should not be used.

7- Completely Detailed

One major characteristic of a good SRS document is that it has complete details of every requirement. Also, the functions of the software must be appropriately explained. When the document is reviewed, it is the responsibility of the team to check whether every part of it is complete or is missing out any details.

8- Consistent

Consistency refers to the ability of the SRS document not to overlap any requirements mentioned in it. For example, no conflict between the time period or product costs should occur in the document.

9- Verification

The verifiability of each requirement mentioned in the SRS document is also important. Every requirement should be quantifiable to its extent of implementation before adding it to the software.

10- Traceable

The last important characteristic of a good SRS document is the traceability of requirements. It means that the background and need of adding a requirement as well as its implementation in the code segment should be traceable. It helps to ensure the feasibility of the requirements in SRS.

Read more about MVP development at ENOU blogs.

Template of an SRS document

We have prepared the template below to help you follow a well-made template for your Software requirements specification document. You can follow these headings and subheadings in your SRS document.

  1. Table of Contents
  2. Introduction
    • Purpose
    • Scope
    • Intended Audience
    • Intended Use
    • Definition
  3. Software Description
    • Product Features
    • User Needs
    • Operating Platform
    • Design & Implementation Limitations
    • Assumptions
  4. Software Requirements
    • Functional Requirements
    • Non-Functional Requirements
    • External Interface Requirements
    • Domain Requirements
  5. System Features
    • Description
    • User Interface (UI)
    • Hardware Interface
    • Software Interface
  6. Other Requirements
    • Performance Requirements
    • Security Requirements
    • Safety Requirements
    • Quality Requirements
  7. Appendix
  8. References

IEEE 830 Software Requirements Specifications

The Software Engineering Standards Committee of the IEEE Computer Society has set specific standards for writing an SRS document. According to IEEE standards, there are certain benefits that a good SRS should provide to customers, suppliers, and other individuals. These benefits are mentioned below.

  • The product’s functionality should be established as the basis of the customer and supplier agreement.
  • An SRS document should be able to reduce software development efforts by revealing any omissions, misunderstandings, and inconsistencies in the SDLC.
  • A realistic estimate of project costs and schedule should be shown in the document.
  • A good SRS provides a baseline for the verification and validation of the software.
  • It should serve as a basis for later enhancement of the final product.

For reference, see IEEE Recommended Practice for SRS.

Conclusion

Writing an SRS document is a major part of the SDLC process. A professional team has to commit to making a clear, concise, and detailed SRS document. A Software requirements specification document functions as an implementation plan for the software, which is why it is necessary to pay attention to detail.

It aids in developing an understanding between the developers and the clients and omits any mistakes that could occur in the software beforehand. It also gives an overview of the risk analysis of the system. For so many reasons described in this blog, an SRS document is important and should be written to serve its purpose. We have provided you with a good template to follow whenever you are writing an SRS document. We hope this blog helped you understand the process of writing an SRS document.

FAQs

Is SRS Like a Request for Proposal (RFP)?

In some ways, an SRS document is similar to RFP but there is a difference in the functionality of both. An RFP is written by the client enlisting the necessary details for the development team whereas an SRS document includes detailed technical information related to the project.

Where Should I Write a Software Requirements Specifications Document?

You can write your SRS document in MS Word. First, create the template for your SRS document in MS Word. However, to save time and ensure accuracy, you can write your SRS document in Helix ALM. Helix ALM is an ALM software tool that can help you write your SRS document easily.

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