Writing Requirements

A guide for writing effective requirements.

Requirement Structure

### REQ-01: Requirement Title

- The system SHALL [action] [result] under [condition]

ID Format

REQ-XX

• REQ: Requirement prefix
• XX: 2-digit number (01, 02, ...)

Characteristics of Good Requirements

1. Clear

Bad example:

The system should respond quickly

Good example:

The system SHALL respond within 200ms for 95% of requests

2. Verifiable

Bad example:

The system should be easy to use

Good example:

The system SHALL allow access to main features within 3 steps

3. Independent

Each requirement should be implementable/testable independently.

4. Traceable

Reference requirement IDs in code and tests:

/**
 * @spec REQ-01
 */
function login() {}

Requirements by Category

Functional Requirements

### REQ-01: User Login

- The system SHALL support email/password login

Security Requirements

### REQ-02: Password Storage

- The system SHALL hash passwords using bcrypt before storing
- The system SHALL NOT log plaintext passwords

Performance Requirements

### REQ-03: Response Time

- The system SHALL return API responses within 500ms
- The system SHOULD support 1000 concurrent users

Accessibility Requirements

### REQ-04: Keyboard Accessibility

- The system SHALL make all features accessible via keyboard

Priority Notation

### REQ-01: Login [HIGH]

### REQ-02: Social Login [MEDIUM]

### REQ-03: Biometric Auth [LOW]

Dependency Notation

### REQ-03: Password Reset

- The system SHALL send reset link via email
- **Dependency**: REQ-01 (Login)

Validation Checklist

• [ ] RFC 2119 keywords used?
• [ ] Verifiable conditions?
• [ ] Specific numbers/criteria?
• [ ] Clear subject and verb?
• [ ] ID format followed?