How to Write Software Requirement Specification (SRS) Doc (with example)

What is a Software Requirement Specification

What is SRS? A Software Requirements Specification, also known as a SRS, is a document that describes in detail the functional and non-functional requirements of a software system. It serves as a blueprint for software developers, guiding them in the design, development, and testing of the software.

In the realm of software development, success hinges upon clear communication and effective project management. A crucial element in achieving these objectives is the Software Requirements Specification (SRS). While often referred to as SRS, software requirements document, it is formally known as the Software Requirements Specification document.

This comprehensive guide serves as the foundation for any software project by defining its objectives, features, and constraints.

In this article, we will delve deeper to help you understand the software requirement specification meaning, importance of a well-defined SRS, its key components, the tools available for creating and managing SRS documents, the vital process of reviewing and validating the SRS, and the indispensable role of stakeholders in the SRS process and - you can find here a software requirement specification document example (a template with hints and examples of content).

The Importance of a Well-Defined SRS

A well-defined Software Requirements Specification is the cornerstone of a successful software project. It acts as a bridge between the client's expectations and the development team's understanding. Here's why it's so vital:

1. Clear Communication: An SRS provides a common language for all stakeholders. It eliminates ambiguity, ensuring that everyone is on the same page regarding project goals, functionalities, and constraints.
2. Efficient Planning: A comprehensive Software Requirements Specification aids in project planning and estimation. It allows developers to create a roadmap, allocate resources, and set realistic timelines.
3. Scope Control: It helps in managing the project scope effectively. Any changes or modifications can be traced back to the requirement specification document, preventing scope creep and unexpected deviations.
4. Quality Assurance: By clearly defining requirements, the SRS becomes a benchmark for quality assurance. It enables rigorous testing to ensure that the final product aligns with the client's needs.

Components of an SRS Document

To understand what is a software requirement specification, let's delve deeper into its key components and their purpose.

A well-structured Software Requirements Specification document typically comprises the following components:

1. Review & Revision History: in the revision history section you would post date of revision, what has changed, and who changed the document (authors of the changes). In the software requirements specification template below you'll find the review&revision history table.
2. Approval: This is actually your sign off history, who approved each version of the document - you keep this in the Approval History table. If not approved but reviewed, or approved by a decision maker AND reviewed by other stakeholders - still keep Approvals and Reviews separate.
3. Introduction: This section provides an overview of the software project, including its purpose, scope, and objectives. The introductory section discusses the business objectives and how the software project aligns with those objectives. It sets the context for the technical requirements. This is a somewhat short chapter but this chapter is definitely the most complex. To put in all the objectives and the core of the product idea, a product discovery shall happen. For example, the product manager shall define the customer value journey before the appearance of any functional requirements.
4. Assumptions Section: The SRS document may have a dedicated section or subsection where assumptions are explicitly listed. This section is used to make stakeholders aware of any conditions or expectations that are taken for granted during the software development process.
5. Constraints: Business constraints, such as budget limitations or regulatory requirements, may be documented in the requirement specification document to ensure that the software project stays within the defined constraints.
6. Functional Requirements: Here, the document outlines the specific features and functionalities the software must deliver. Some business requirements may translate into functional requirements in the software requirement specification. For example, if a business requires an e-commerce website to increase online sales, this can be translated into specific functional requirements, such as implementing an online shopping cart, a secure payment system, and user account management.
7. Non-Functional Requirements: These encompass constraints, performance expectations, and qualities like security, scalability, and usability. In the software requirements specification template you'll see the examples of the non-functional requirements.
8. Data Models: Explains how data will be structured and manipulated within the software.
9. System Architecture: Describes the overall structure and components of the system, including hardware, software, and data flow.
10. Dependencies: Lists any external systems, libraries, or components the software relies on.
11. Testing and Validation: Outlines the approach to testing and validation, including acceptance criteria.
12. Glossary: A list of terms and definitions used in the document to ensure consistent understanding.

So, having all the chapters mentioned, we can now better understand what is a software requirement specification.

Tools for Creating and Managing Software Requirements Specification Documents

To create and manage SRS documents efficiently, there are several tools available, including:

1. Microsoft Word: A widely used word processing software for creating well-structured documents.
2. Google Docs: A collaborative platform that allows multiple stakeholders to work on the SRS simultaneously.
3. Software Requirement Management Tools: Specialized tools like Jama Connect, Helix RM, and IBM Engineering Requirements Management DOORS, designed for SRS creation and management.
4. Version Control Systems: Using version control systems like Git, teams can keep track of changes and maintain a history of the software requirement specification.
5. Confluence (Atlassian) - I, personally, use Confluence - it has the word processing functionality, macroses for linking, or inserting schemas, version control and view tracker - a perfect mix for a requirement specification document.

The software requirements document template below was created in Word (to make it easier to upload, download and share). But you can copy it and past anywhere, for example, to Confluence or Google Doc.

Reviewing and Validating the SRS Document

Review and validation of the SRS are critical to ensure its accuracy and completeness. The process involves the following steps:

1. Peer Review: Team members and stakeholders should review the SRS document to identify errors, inconsistencies, or missing details.
2. Validation: The Software Requirements Specification must be validated against the client's requirements to ensure that it accurately represents their needs.
3. Client Approval: The final software requirements document should be approved by the client or key stakeholders before proceeding with development.

In the software requirements document template below you'll see the review and approval history - this shall be documented in the software requirements document.

The Role of Stakeholders in the SRS Process

Stakeholders play a pivotal role in the SRS process, including:

1. Clients: They provide the initial requirements and validate the SRS document to ensure it aligns with their vision.
2. Project Managers: They oversee the creation and management of the SRS, ensuring it adheres to project goals and timelines.
3. Developers: They rely on the Software Requirements Specification to guide the development process, understanding what needs to be built and how it should function.
4. Testers: The SRS document serves as a basis for developing test cases and validation procedures.
5. Quality Assurance Teams: They use the SRS to ensure the final product meets the specified requirements and quality standards.

Download SRS document Template

In the document below, you can find a template and try to create your own using hints and examples there. Learn how to Write Software Requirement Specification (SRS) Document right now! (You can find some software requirements document example (some examples of the items in the chapters) in the template)

Conclusion

A well-defined Software Requirements Specification is the cornerstone of successful software development. It provides clarity, sets expectations, and serves as a reference point for all project stakeholders. With the right components, tools, and a rigorous review process, the Software Requirements Specification can ensure that a software project meets its goals and satisfies its clients' needs. Moreover, stakeholders' active involvement throughout the process is essential to guarantee the project's success. Therefore, never underestimate the power of a well-crafted software requirements specification in the software development lifecycle.

Related

If you are a Business Analyst or a Product Manager, or are considering becoming one and contemplating obtaining a Product Owner certificate, you might find this article of interest: How to become a Certified Scrum Product Owner?

Writing SRS is just one thing among the others business analysts should master. Read more about Business Analyst Skills

Find more about day-to day activities and tools of BA reading Business Analyst Books