What it is
A Software Requirements Specification (SRS) defines the complete set of functional and non-functional requirements for a software system. It serves as the single source of truth for stakeholders by describing what the system must do and how it should behave.
An SRS typically includes system overview, functional requirements, data definitions, integrations, business rules, non-functional requirements, constraints, and assumptions-forming the foundation for design, development, testing, and project planning.
Purpose and Benefits
- Defines requirements clearly: Complete description of capabilities and behavior.
- Aligns stakeholders: Shared understanding for owners, engineers, and QA.
- Reduces ambiguity: Prevents rework through precise documentation.
- Supports dev and testing: Builds features and test cases from one source.
- Enables traceability: Links business needs to features, dev, and QA.
- Supports governance: Reference for scope management and change control.
Recommended SRS Structure
| Section | Details | Template |
|---|---|---|
| Introduction | Overview of the system, purpose of the document, and target audience. | - |
| System Overview | High-level description of the system and its context. | - |
| Project Goals | Business objectives the system aims to achieve. | Project Goal Template |
| Stakeholders | Key stakeholders and their roles. | Stakeholder Template |
| Scope (In Scope / Out of Scope) | Defines system boundaries and exclusions. | In Scope & Out of Scope Template |
| Assumptions & Constraints | Project assumptions and limitations. | Assumptions & Constraints Template |
| Functional Requirements | System features and expected behavior. | Feature List Template |
| Feature List | List of core product features. | Feature List Template |
| User Stories / Use Cases | Detailed user interaction scenarios. | Use Case Template |
| Business Rules | Policies and logic governing system behavior. | Business Rules Template for Software Projects |
| Data Model / Data Fields | Definitions of system data elements. | Data Field Definition Template |
| Integration & External Systems | Third-party systems and APIs. | Integration & External Systems Template |
| API Specifications | API endpoints and integration details. | API Specification Template |
| Non Functional Requirements | Performance, security, availability, scalability, UX. | Non-Functional Requirements (NFR) Template |
| Risks & Mitigation | Identified project risks and mitigation plans. | Risks & Mitigation Template |
| Test Cases | Verification scenarios to validate requirements. | Test Case Template (Manual Testing Example) |
| Requirement Traceability Matrix | Traceability between requirements and tests. | Requirement Traceability Matrix Template |
| Change Request Log | Documentation of scope or requirement changes. | Change Request Log Template |
SRS Worksheets
1. Introduction
- Purpose of the system
- Intended audience
- Document scope
- Definitions and acronyms
2. System Overview
- High-level description of the system
- Business context
- Key system capabilities
3. Project Goals
| # | Goal Statement | Success Criteria | Owner | Timeline | Notes |
|---|---|---|---|---|---|
| 1 | |||||
| 2 | |||||
| 3 |
4. Stakeholders
| Stakeholder ID | Stakeholder Name | Stakeholder Type | Role / Title | Department / Org | Responsibilities | Involvement | Contact Mode | Notes |
|---|---|---|---|---|---|---|---|---|
5. Scope (In Scope / Out of Scope)
| Scope | Details |
|---|---|
| In Scope | |
| Out of Scope |
6. Assumptions & Constraints
| Category | Description |
|---|---|
| Assumption | |
| Constraint |
7. Functional Requirements
| Feature ID | Feature Name | Description | Module | Priority | Status | Owner | Notes |
|---|---|---|---|---|---|---|---|
| FTR-001 | |||||||
| FTR-002 | |||||||
| FTR-003 | |||||||
| FTR-004 |
9. User Stories / Use Cases
| Use Case Field | Value |
|---|---|
| Use Case ID | UC-001 |
| Use Case Name | User Login |
| Actor | User |
| Description | Allows users to log into the application |
| Preconditions | User must have a registered account |
| Main Flow | 1. User opens login page 2. Enters email and password 3. Clicks login |
| Alternate Flow | If credentials are invalid, show error message |
| Postconditions | User successfully logged in |
| Priority | High |
| User Story Field | Value |
|---|---|
| Story ID | US-001 |
| User Role | Customer |
| User Story | As a customer, I want to create an account, so that I can place orders. |
| Acceptance Criteria | Email must be unique |
| Priority | High |
| Story Points | 5 |
| Status | Ready |
| Notes | Basic onboarding |
10. Business Rules
| Rule ID | Rule Name | Description | Condition | Action / Outcome | Related Feature | Priority | Notes |
|---|---|---|---|---|---|---|---|
| BR-001 | |||||||
| BR-002 | |||||||
| BR-003 |
11. Data Model / Data Fields
| Field ID | Field Name | Description | Data Type | Format / Length | Required | Validation Rules | Example Value | Notes |
|---|---|---|---|---|---|---|---|---|
| DF-001 | ||||||||
| DF-002 |
12. Integration & External Systems
| Purpose / Why needed | Direction | Owner / Team | System Name | Data Exchanged |
|---|---|---|---|---|
| Process online payments for wallet transactions | Bi-directional | Payments Team | Payment Gateway | Payment authorization requests, transaction status, settlement confirmations |
| Verify customer identity during account creation | Outbound | Compliance Team | KYC Verification Service | Customer identity data, verification results |
| Send transactional notifications to users | Outbound | Messaging Team | Notification Service (Email/SMS) | Email addresses, phone numbers, notification content |
| Sync customer profile data across enterprise systems | Bi-directional | Data Integration Team | Customer CRM System | Customer profile information, account status updates |
| Provide authentication for mobile users | Bi-directional | Security Team | Identity Provider (OAuth/SSO) | Authentication tokens, user identity information |
13. API Specifications
| Field | Value |
|---|---|
| API Name | Create Wallet Account |
| Endpoint | /api/v1/wallet/create |
| Method | POST |
| Request | { "name": "John Doe", "email": "john@example.com", "phone": "+1234567890" } |
| Response | { "wallet_id": "WLT1001", "status": "created" } |
14. Non-Functional Requirements
| Category | Details |
|---|---|
| Performance | 1. App startup: cold <= 2s; warm <= 500ms. 2. Payment flow P95 <= 1.5s. 3. API latency P95 <= 300ms, P99 <= 1s. 4. Local wallet ops P95 <= 100ms. 5. Throughput 200 RPS sustained. |
| Scalability | 1. Up to 100,000 concurrent active users. 2. Horizontal autoscaling for services. 3. Storage scales to 100M wallet records. 4. Queues scale dynamically for payments. |
| Availability | 1. Uptime >= 99.95% monthly. 2. Critical payments >= 99.9%. 3. DR RTO <= 1h, RPO <= 15m. 4. Graceful degradation keeps core payments running. |
| Security | 1. MFA with biometrics + PIN. 2. RBAC for admin access. 3. TLS 1.2+ in transit, AES-256 at rest. 4. Keys via KMS/HSM with rotation. 5. Audit logs retained >= 1 year. 6. Fraud detection rules for suspicious activity. |
| Usability & UX Quality | 1. Primary payment flow <= 3 steps. 2. Success/failure feedback <= 1s. 3. First-time setup <= 5 minutes. 4. WCAG 2.1 AA compliance. 5. Localization for currency, date, time, languages. |
| Other Requirements | 1. Push notifications P95 <= 5s. 2. Telemetry overhead <1%. 3. PCI-DSS compliance for card transactions. 4. Audit/compliance reports on demand. |
15. Risks & Mitigation
| # | Risk | Mitigation |
|---|---|---|
| 1 | Payment gateway integration delays due to third-party API issues | Identify backup payment gateway provider and start integration testing early |
| 2 | High transaction volume causing system performance issues | Implement autoscaling infrastructure and conduct load testing before launch |
| 3 | Security vulnerabilities leading to data breaches | Perform security audits, penetration testing, and enforce strong encryption standards |
| 4 | Changes in regulatory requirements affecting compliance | Maintain communication with compliance teams and monitor regulatory updates |
| 5 | Mobile app compatibility issues across devices | Test across multiple OS versions and device types during QA phase |
| 6 | Dependency on external notification service outages | Implement fallback notification provider and retry mechanisms |
16. Test Cases
| Test Case ID | Feature / Module | Test Scenario | Test Steps | Expected Result | Actual Result | Status | Priority | Tester |
|---|---|---|---|---|---|---|---|---|
| TC-001 | User Login | Verify login with valid credentials | 1. Open login page 2. Enter email and password 3. Click Login | User should login successfully | - | Not Run | High | QA Team |
| TC-002 | User Login | Verify login with invalid password | 1. Open login page 2. Enter incorrect password 3. Click Login | Error message displayed | - | Not Run | Medium | QA Team |
| TC-003 | Password Reset | Verify password reset functionality | 1. Click Forgot Password 2. Enter email address 3. Submit request | Reset link sent to registered email | - | Not Run | High | QA Team |
17. Requirement Traceability Matrix
| Rule ID | Rule Name | Description | Condition | Action / Outcome | Related Feature | Priority | Notes |
|---|---|---|---|---|---|---|---|
| BR-001 | Minimum Age Requirement | User must meet minimum age to register. | If age < 18 | Registration rejected | User Registration | High | Regulatory requirement |
| BR-002 | Payment Verification | Order can only be confirmed after successful payment. | Payment status = Success | Confirm order | Order Processing | High | Applies to all payment methods |
| BR-003 | Order Cancellation Window | Customer can cancel within 24 hours of purchase. | If time since purchase < 24 hours | Allow cancellation | Order Management | Medium | Exclude shipped orders if applicable |
18. Change Request Log
| Change ID | Change Title | Description | Requested By | Request Date | Impact (Scope/ Cost/ Time) | Priority | Status | Owner | Decision |
|---|---|---|---|---|---|---|---|---|---|
| CR-001 | |||||||||
| CR-002 | |||||||||
| CR-003 |
Appendix
Add diagrams, workflows, UI mockups, data flow diagrams, and any reference materials that support the SRS.