31 March 2022

Software Requirements Specification: What Is It and How to Get It Right?


Entrusting your software development project to developers based only on oral communication or simple notes is bound to fail. If you want to avoid a chaotic implementation process, the disappointing performance of your product, or, worst-case scenario, a total failure of your project, I advise you to take some preparations. 

If you want your project to go as smoothly as possible, it’s absolutely crucial to write everything down. That’s why you need a Software Requirements Specification (or an SRS document). 

What is SRS? 

Software Requirements Specification is one of the most important documents in software development. SRS document provides guidelines and specifications for the project and serves as a written analysis of customer requirements. It states what the client would like to achieve by creating the system. 

It helps the designer to design the system and provides them with all the information, such as definitions for the functional and non-functional requirements of the software, as well as the purpose of the project. Programmers use the SRS as a reference point to understand business needs and requirements. 

Why Is SRS important? 

Software Requirements Specification plays an important role in the development process, for both developers and stakeholders, as it clearly defines the scope of the project. It guides developers through all the intricacies of the project, explaining thoroughly what is expected from the solution and what final product they should come up with. By describing all the details and expectations, SRS document minimises the amount of time and effort needed to finish the product. Consequently, it can also reduce the overall cost of development.  

And that’s not all! If composed properly and clearly, SRS reduces the possibility of future redesigns and minimises the risk of mistakes in understanding customer expectations on the part of developers. It also ensures clear and reciprocal communication between the client and developers, clarifying all the doubts and stating all the important details. It’s also worth mentioning that it also serves as the document to verify the testing processes. Based on SRS, other documents are created, such as Test Scenarios, which are used in User Acceptance Tests

How to Write a Software Requirement Specification Document 

If you want to organise your SRS document properly, I advise you to start with some general information on the software, and finish by adding all the details to give a full picture. I also want to emphasise that SRS documents are drafted with the very significant participation of the ordering party and close cooperation, continuous verifications and customer acceptance are key in the process of creating the SRS. 

Knowing that, here’s a list of steps you should take during creating a Software Requirement Specification Document. 

Create an Outline 

The first step you need to take when writing your SRS document is to create an outline that summarises all the elements described and defined in the document. You can write it by yourself or use an existing SRS template to save some time. 

Define the Purpose 

Once you’re done with an outline, it’s time to get down to details. At this point, you should define the purpose of the product and scope of the project, the value it will deliver, as well as intended users and the way they will use the product. 

Give an Overview 

After defining the product’s purpose, it’s time to summarise how will it work. In this part, you give a general description of features and how will they respond to the user’s needs. You should also describe the assumptions about your product’s functionality. 

Finally, you should note if your project is dependent on any external factors. Is it a new product? Is it an add-on to a product you’ve already created? Is this going to integrate with another product? 

Describe Functional and Non-functional Requirements 

Now that you have written the general information, it is time to get more specific. Completing the overview before working on functional and non-functional requirements gives you a reference to make sure you are meeting the user's basic needs when filling in the details. 

The detailed description of the system requirements is the most important component of an SRS document. Make sure that you describe the functional requirements in substantial detail to facilitate developers’ work. However, don’t underestimate the importance of non-functional requirements such as security specifications and performance. 

To vividly describe how users will interact with your system, I advise you to add use cases.  

Add Supplemental Details 

The last step in creating the draft of SRS document in software engineering is adding any details that could help developers finish their job in the form of appendixes, glossaries of terms, and references. 

Get Approval 

Once you’re done with your SRS draft, it’s time to get official approval from the stakeholders. That will probably require you to prepare and present a presentation to the people involved in the development process. 

Don’t be surprised if they ask for some changes and update the SRS document based on stakeholder feedback. However, don’t ger discouraged. It’s actually a good sign, as it means both developers and stakeholders are making the document more precise, so the project is more likely to succeed. 

Successful Project Delivery 

Clear, concise, and executable requirements can significantly help development teams create a proper product. If you want your project to go as smoothly as possible, focus on close cooperation between all the involved parties.

Without having all requirements set, a project is likely to result in an enormous waste of money, effort, and time. 

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Karol Parafianowicz
Senior Project Manager