Writing Software Requirements Specification Guide

February 16, 2024

Do you want to write a Software Requirement Specification (SRS) Document but are unsure how to go about it? Are you stuck wondering if it's even necessary to write one? Then we've got the right information for you right here.

Here at Cloud Employee, we work with companies looking to hire professional offshore developers in the Philippines. Our work has seen many SRS documents pass through our hands. If you need to write an SRS for your business, and you’re wondering how to write an airtight document, this article will help.

We'll address the usefulness of an SRS letter, detailing all the different ways several parties in the development process can use it. Finally, we’ll provide several essential tips on how to go about writing an effective SRS letter for your software project.

What is a Software Requirements Specification (SRS) Document?

If you are unfamiliar with the term 'Software Requirements Specification (SRS) Document,' you are not alone. To give you a better understanding of what the term means, an SRS document basically gives a detailed description of what your software will do and how it is anticipated to perform. In addition to that, the document details the functionality of the software and how it will fulfill the needs of all stakeholders. The average SRS document consists of a purpose, an overall product description, and specific requirements to be followed.

An SRS document is crucial, especially when you are outsourcing the development of your software project. It ensures that you cover all the necessary details about the product and exactly how you want it to turn out. This means that your developers will have a clearer picture of what you want, leaving little room for error or confusion. An SRS document almost guarantees that the vision you have in your head and the finished product match.

Why use an SRS document?

As aforementioned, an SRS document allows you to paint a clear picture of exactly how you want your software product to turn out. It translates your idea into a language that your developers will understand. To ensure that developers deliver what you, or your client, want, you need to put together an SRS document. In fact, a lot of people regard this document as a form of the written agreement between both parties on every detail of the software.

In addition to being a developer's detailed guide to building your software, an SRS document can also help your coders plan their work and get an idea of the tech stack they'll need, as well as help you estimate the cost of executing the project. If you think that's all a Software Requirements Specification (SRS) Document is good for, you couldn't be any further from the truth. Other uses of this document include:

  • Presenting designers with a project insight so that they can match the design to use case
  • Aiding end users to understand the software
  • Providing investors with an outline of the software's features and assisting them in making their investment decisions
  • Helping testers create cases that fit the needs of the business

As you can see, this single aspect of the document provides clarity for project managers, designers, developers, investors, and testers.

How to write an SRS Document

Now that you know what an SRS document is and its usefulness let's get into the main discussion on how to go about writing one. Writing this document can sometimes come across as complicated, but in reality, it is a very straightforward process. As long as you have a complete idea of how you want your software to turn out and what you want it to do, you can easily write a substantial SRS document in good time. To get you started on writing an apt software requirements specification document, here are a couple of helpful tips:

1. Create an outline:

The first thing you're going to want to do when drafting your SRS document is to create an outline of what is included. You have two options when creating an outline. You can either build it yourself from scratch, or you can use an SRS template to get you started. You can easily find a good SRS template online, and it basically provides you with all the sections you would need to draft your document.

The sections typically included in an SRS outline are an introduction, a purpose, intended audience, intended use, scope of the project, definitions, overall description of the software, needs of users, dependencies and assumptions, and finally, system features and requirements (which consists of functional requirements, external interface requirements, system features, and non-functional requirements).

2. Describe the purpose:

After you've created an outline for your document, the next step involves describing your software/product's purpose. This essentially allows you to paint a clear picture of what you want your product to do and how you want it to function. When describing your software's purpose, you should also include details about the intended users and how you want them to use the product.

This way, during the development and design process, your workers know exactly how to create the product. To provide a good structure for your purpose, you should:

  • Define the scope of the project, outline the value that it will deliver to users
  • Give a description of the target audience for the software, and finally, describe how your software will help your intended user to live or work better.

3. Provide an overview:

Ensuring that you provide an overview of your product is essential. This is because an overview gives a summary of how your product will function. When writing an outline, include details about your software's features and how they will work to meet the users' needs. In addition to this, you'll also need to define any assumptions you are making about the software and its functionality.

You can end by describing any dependencies that your software may have on any other products in the tech ecosystem. This can help your developers create the software to operate seamlessly with the apps or websites they depend on.

4. Define your functional and non-functional requirements:

With an overview, you provide general information about the product. Writing your overview before detailing your functional and non-functional requirements is important and intentional. This is because your overview gives you something to refer back to in order to ensure that your product meets the basic needs of the users while you work on the details.

Once you've gotten your overview, it's time to get into the specifics. This part is actually the most important aspect of writing an SRS document. So it's advisable not to skip it, or glaze over for any reason.

Here, you should describe the functional and non-functional requirements of the software by providing as many details as possible so that the developers can start work. Ensure that you give details about how users can operate your system. Also, provide information about your project's objectives as this can help you measure the progress of the project during the development stage.

5. Include any additional details:

At this point, you have probably reached the final stage of drafting your SRS document. The last step often involves providing any additional details you may have left out. For the most part, you can't catch every single detail in the previous stages. It's impossible to express how important it is to do this; it should not be overlooked because describing additional information can actually help developers to finish their job without having to worry about dealing with loose ends afterward. Once you've provided this, you have basically concluded the draft of your software requirements specification document, and you can move on to the final step.

6. Get approval for your document:

Once you have finished writing your SRS document and included all the necessary details, you need to present the document to your stakeholders to get it approved. You'll likely need to make a presentation in front of all stakeholders involved in the development, design, and testing stages. If you're not articulate enough, get the most competent members of your team to do this.

Be prepared for them to ask for changes, and when they do, update the document to reflect it. It'll be negligent not to add any updates, and the final product can suffer for that. After responding and adjusting to feedback from your stakeholders, you will typically get your document approved. With stakeholders and developers on the same page, this means that your project can finally take off and is less likely to go off track.

To Summarise

Writing an SRS document may seem complicated at first, but once you have a good idea of how you want your product to turn out, it's pretty much smooth sailing. Moreover, if you follow our useful tips, you will find it easy to put together an effective and detailed document. As you already know, this document is particularly important.

It provides your developers with all the essential details they need to execute your project to best match what you want properly. Even more, it equally acts as a one-stop source of information for other parties, including designers, testers, and investors.