Whenever a development team start to make an app, it’s best to have the requirements and info of the app written and approved by the team. That’s where SRS or Software Requirement Specifications comes in.
SRS is a document containing precise and comprehensive info about how a software work and what goals it is aiming to solve.
In this article we will check out together:
- What is SRS Document (Software Requirements Specification)?
- Why we should write an SRS document?
- What’s the difference between Software Requirements Specification versus System requirement Specification?
- How to write an SRS document?
What is SRS Document (Software Requirements Specification)?
In general an SRS is a document explaining precisely how a software should work and what will deliver.
Also it is describing the business and user goals of the software as what problem it will fulfill.
SRS is a roadmap to the software which is going to build. SRS can be divided into 4 Ds:
- Define
Define your software’s goal. In this section, it explains what is the goal of the software and what gap the software will fulfill.
- Describe
Describe what is going to build. Whether it is an app or software or both it will explained here what is going to build.
- Detail
Detail the requirements. In this section it is getting explained precisely how each feature is working usually through user stories.
- Deliver
Deliver it for approval. The SRS should always delivered to the stakeholders for approval before starting to implemented.
A good SRS document is the one which defines everything from how it will work when embedded to the hardware to how it will perform when used in different software.
It can go further and explain the needs of real-life users and their interactions.
Why we should write an SRS document?
Writing an SRS is a necessary step in developing a software. It is also used in Startups but it’s out of scope of this article.
As the saying “Failing to plan is planning to fail”, it is the same with software. Developing a software without a properly written SRS will result in unexpected consequences.
Sometimes teams oversee the importance of a well described SRS due to lack of time, but in the end it happens to cost even more time to the team when the work has been done incorrectly or in a different way.
SRS documents creates a framework for the dev team to know what they will work on and how they will achieve this.
It also helps the other teams as QA, Operations and maintenance. Also it will coordinate the teams to ensure the requirements are fulfilled and delivered in the way they need to be.
Without a detailed plan or SRS, teams can run in circles, come up with hundreds of errors, miss deadlines, overrun costs and even it can threaten existence of a software company.
What’s the difference between Software Requirements Specification versus System requirement Specification?
In SRS “software” and “system” sometimes are getting used interchangeably. So what’s the difference between the two?
Usually a software requirements specification provide more detailed info than a system requirements specification.
System Requirements Specification sometimes called SyRS to differentiate it from Software Requirements Specification. SyRS provides general info on the requirements of the system which can include both software and hardware needs. The main focus in SyRS is on the system itself based on the business needs analysis.
On the other hand SRS (Software Requirements Specification) provides details of the software going to developed.
How to write an SRS document?
Clear a clear and comprehensive SRS document may need an enormous effort and time but it is one of the vital steps in developing and delivering a high quality software.
Here’s the steps to create an effective SRS document
Define the goal of the software
You can define the goal of your software by creating an outline yourself or by using an existing template.
If your making your own template it can be similar to the following titles and sections. This is a basic requirements it can be more or less depending on your specific project.
- Introduction
- Purpose
- Intended audience
- Intended use
- Product scope
- Definitions and acronyms
- Overall description
- User needs
- Assumptions and dependencies
- System features and Requirements
- Functional requirements
- External interface requirements
- System features
- Nonfunctional requirements
Define the product’s purpose
This is a vital part of the conducted SRS document. When team members navigating through the SRS, a lot of time they come back to this section to understand the goals of software and based on it, they understand the further info inside the document.
Target audience and use
Clearly explain whom in the team will have access to this document and will use it. These include developers, testers and managers. In addition stakeholders, leadership teams, sales, marketing and customer may use it time to time.
This will reduce costs effectively in the future.
Scope of the product
Why this product is getting created? Overall business goals will be explained in this section. This is particularly useful when teams other than development have access to it.
Glossary
It’s best to provide a glossary section to make sure everyone is on the same page. Key terms and acronyms are all explained here and the document get created based on it.
In this way, there will be less vague content and more clear info.
Describe what is going to build
In t5his step we will explain how part of the software. Also it will described who this product is for, it it an stand alone product or a plugin for an existing software. Anything related to the product will be explained here.
Knowing everything about how will the product work in advance, will enormously help the team for developing higher quality product.
End user needs
It’s an important part of writing SRS to define different user roles and their needs. Each user type should be described and explained how they will use the app.
It’s better to categorize user types and explain the related info in separate parts. SO in this way accessing to different info is more accessible and easier.
Dependencies and assumptions
It is very helpful to point out clearly what are the assumptions in this project. It will help all team members to be on the same page.
In this section all third party services and tools, all the infrastructure services and tools that we use should be explained.
Also another advantage of stating the assumptions is it will help in identifying future risks involved in these third party dependencies.
Detail your specific requirements
This is where all the details about the product is getting mentioned. How much the SRS document written in more detailed info, it will help the team that much.
Sometimes it feels overwhelming but categorizing the features and info always make life easier.
It can easily categorized to different sections as functional requirements, system requirements, interface requirements and different types of on functional requirements.
Functional requirements
This is the main part of your SRS document. As the name suggests, in this section functionality of your software will be explained.
Questions like, “what function this feature provides?”, “what this feature add to my software” and similar questions will help you understand your software’s functionality in a better way and explain it in more clearly.
This part can also include info about how the software will interact with third party services and apps, or how it will work inside other apps, if needed.
External interface requirements
Based on your project nature, it might need to explain external interface requirements. This is usually done in embedded systems. It is explained how your product will interact with external components.
Requirements are getting written for different types of interfaces, including:
- Communications
- Software
- Hardware
- User
Features of the system
System features is a subset of functional features. It is explaining the requirements for your software as a system. Basically what your software as a system entity will do, is explained here.
Non functional requirements
Non functional requirements can be as important as functional requirements. It will ensure the product will work as expected for both the users and stakeholders.
Non functional requirements may include:
- Security requirements
- Scalability requirements
- Usability requirements
- Performance requirements
Deliver the software for approval
Well, it’s not an step for writing an SRS document, but after the software developed, stakeholders and managers will review the SRS document and approve the developed software based on it.