What is Software Requirements Specification
(SRS) ?
A Software Requirements Specification (SRS) is a detailed document that describes the functional and non-functional requirements of a software system. It serves as a blueprint for developers, testers, and stakeholders, ensuring everyone has a clear understanding of what the software should do and how it should perform. The SRS is a critical part of the software development lifecycle (SDLC) and acts as a contract between the development team and the stakeholders.
Purpose of SRS
- Define Requirements: Clearly outline what the software should achieve.
- Guide Development: Provide a roadmap for developers to build the system.
- Ensure Alignment: Ensure all stakeholders (business, development, testing teams) are on the same page.
- Facilitate Testing: Help testers create test cases to validate the system.
- Serve as a Reference: Act as a single source of truth for the project’s requirements.
Key Components of an SRS
An SRS typically includes the following sections:
1. Introduction
- Purpose: Why the document is being created.
- Scope: What the software will and will not do.
- Definitions: Key terms and acronyms used in the document.
- References: Links to related documents (e.g., BRD, project charter).
- Overview: A high-level summary of the document.
2. Overall Description
- Product Perspective: How the software fits into the larger system or business environment.
- Product Functions: High-level features and functionalities.
- User Characteristics: Who will use the system and their needs.
- Constraints: Limitations (e.g., technology, budget, time).
- Assumptions and Dependencies: Factors that may impact the project.
3. Specific Requirements
- Functional Requirements: Detailed descriptions of what the system should do. Example: “The system shall allow users to log in with a username and password.”
- Non-Functional Requirements: Criteria for how the system should perform. Example: “The system shall handle 1,000 concurrent users.”
- System Features: Breakdown of major features and their requirements.
- External Interface Requirements: How the system interacts with other systems or users.
- Performance Requirements: Speed, scalability, and responsiveness expectations.
- Security Requirements: Measures to protect data and ensure privacy.
- Usability Requirements: Ease of use and accessibility.
4. Appendices
- Glossary: Definitions of technical terms.
- Diagrams: Visual aids like use case diagrams, flowcharts, or wireframes.
Example of an SRS for a Login System
1. Introduction
- Purpose: This document describes the requirements for a user login system for the XYZ application.
- Scope: The login system will allow users to authenticate using their email and password.
- Definitions:
– Authentication: The process of verifying a user’s identity.
– Authorization: The process of granting access to resources based on user roles.
- References: XYZ Project Charter, User Stories.
- Overview: The login system will integrate with the existing XYZ application and provide secure access to users.
2. Overall Description
- Product Perspective: The login system is a module of the XYZ application.
- Product Functions:
- User login with email and password.
- Password recovery.
- Role-based access control.
- User Characteristics: End-users include administrators, employees, and customers.
- Constraints: The system must comply with GDPR regulations.
- Assumptions: Users will have valid email addresses.
3. Specific Requirements
- Functional Requirements:
- FR-001: The system shall allow users to log in with a valid email and password.
- FR-002: The system shall display an error message for invalid credentials.
- FR-003: The system shall allow users to reset their password via email.
- Non-Functional Requirements:
- NFR-001: The system shall respond to login requests within 2 seconds.
- NFR-002: The system shall support up to 10,000 concurrent users.
- System Features:
- Secure password storage using hashing.
- Session management to prevent unauthorized access.
- External Interface Requirements: REST API for integration with the XYZ application.
- Performance Requirements: The system shall handle 100 login requests per second.
- Security Requirements: Passwords shall be encrypted using SHA-256.
- Usability Requirements: The login page shall be mobile-friendly.
4. Appendices
- Glossary: Definitions of technical terms.
- Diagrams: Use case diagram for login and password recovery.
Benefits of an SRS
- Clarity: Provides a clear and detailed description of the system.
- Reduces Ambiguity: Minimizes misunderstandings between stakeholders and developers.
- Improves Quality: Ensures all requirements are met, leading to a high-quality product.
- Facilitates Communication: Acts as a common reference for all project participants.
- Supports Maintenance: Helps in future updates and maintenance of the system.
Best Practices for Writing an SRS
- Involve Stakeholders: Collaborate with business analysts, developers, and end-users to gather requirements.
- Be Specific: Avoid vague language; use clear and precise descriptions.
- Use Visuals: Include diagrams, flowcharts, and wireframes to enhance understanding.
- Review and Validate: Regularly review the document with stakeholders to ensure accuracy.
- Keep It Updated: Update the SRS as requirements evolve during the project.
In summary, a Software Requirements Specification (SRS) is a comprehensive document that defines the what, why, and how of a software system. It ensures that the development team builds the right product and meets stakeholder expectations.