How to Write a Software Requirements Specification (SRS) Document

An efficient IT product development process depends on a clear understanding of project requirements and competent planning of the development flow. To achieve that, a Software Requirements Specification (SRS) Document is created before the work on the project starts.

The document serves as a roadmap for all people working on the project. Trying to work without it is like assembling furniture without an assembly manual: the process will take longer, will be difficult, and certainly have bugs.

A software requirements specification is a document describing what a software product will do and how it will work.

To draw it up in writing you should include a list of product capabilities, constraints, and features. The SRS document takes the wishes of all parties concerned into account, and that makes it useful for any software product design and development, be it a mobile app, website, or desktop utility.

Why You Should Write Software Requirement Specification

To consider the risks, draw up a detailed work pattern, determine the development budget, and minimize unnecessary waste of time and other resources, it is necessary to analyze all project implementation details.

You will be able to make use of the following advantages if you have a clear and high-quality SRS document, which:

• structures and formalizes all project requirements;
• helps the development team build a product that exactly meets customer and target audience needs;
• provides all team members with the necessary information while working on the project;
• minimizes the possible misunderstanding between the members of the development team and the customer;
• clearly defines the scope of work, and that allows developers to plan particular iterations and release dates;
• allows estimating the required development budget;
• simplifies subsequent software enhancements.

Now that you comprehend how beneficial a detailed SRS document is, let us talk about the ways to write good software requirements specifications.

SRS Document Structure

The content of an SRS document will differ depending on the specific project and its peculiarities. On the Internet, you can even find some examples based on real projects.

Here is an example of what a standard SRS document template includes:

1. Introduction

• Purpose
• Document conventions
• Intended Audience and Reading Suggestions
• Project scope
• References

2. Overall Description

• Product perspective
• Product features
• User classes and characteristics
• Operating environment
• Design and implementation constraints
• User documentation
• Assumptions and dependencies

3. System features

[System feature X (several blocks of this kind can be available)]

• Description and priority
• Stimulus/Response sequences
• Functional requirements

4. External interface requirements

• User interfaces
• Software interfaces
• Hardware interfaces
• Communication interfaces

5. Non-functional requirements

• Performance requirements
• Safety requirements
• Software quality attributes
• Security requirements

6. Other requirements

How to Gather Information for SRS

For your SRS document to facilitate better mutual understanding among everyone working on the project, include an exhaustive list of requirements, and formulate the precise wording, it is necessary to collect and unify the requirements from a customer, a development team, and other interested parties.

To solve this issue, you can use the following ways:

1. Individual review. Each team member can give their opinion on what the product should look like. A business analyst collects, organizes, and structures this data.
2. Interview. It means talking to a customer or responsible people on the customer’s side and receiving relevant data from them. This approach is often used when customers are not proficient in the technical part.
3. Project Brief. Customers fill out a brief with pre-composed questions, and after that, the responsible employee on the developer side studies all the answers and records them.
4. Prototyping. It is a great way to visualize a future product in an easy-to-look and simple-to-interact form. Current requirements are recorded, and new ones are identified together with customers.
5. Focus group. The method presumes the process of collecting data based on interaction with the product target audience and potential users as well as polls, interviews, and other ways to know as much as possible about user needs and wishes.
6. Competitor analysis. In this case, you should study existing products on the market to determine the product’s required basic functionality and the features providing a potential competitive advantage.

Depending on the project type, its complexity, and other features, you can use either one of the listed ways of collecting data or some combination.

Aspects That Make High-Quality Software Requirements Document

• The information available in an SRS document should suffice for developers to commence and finish the work on the product. However, you should avoid too much detail if it is clearly unnecessary.
• The requirements have to be consistent with reality, go along with the current technological environment, and comply with available customer resources.
• Any SRS document should be easy to comprehend. Try describing everything as clearly and concisely as possible.
• Avoid ambiguous descriptions and vague and unclear wording — mention exclusively specifics.
• Requirements should be measurable for you to be able to check the finished product for compliance with the specifications described.
• The world of software development is constantly changing, and when the project is implemented, you may need to apply a different tool or technology than the one you planned to use at the beginning. Therefore, you have to envision the possibility to make changes to the document.
• Continuity and consistency are among the important conditions. SRS sections and requirements should not contradict each other.

Conclusion

When working on a project with no document describing the software requirements, you may end up with an unnecessary waste of money and time, and your customer or end-users will be unhappy with the product.

An SRS document is optional, but it will be very useful when you develop medium to large projects. Having it, you can accurately assess the amount of work, calculate the budget, plan the development, and avoid possible misunderstandings in the process.

We can become a reliable technology partner for you and help you build a quality product complying with your budget and requirements. Contact us, and let us discuss the details!