# Functional Requirements
## Purpose
Define comprehensive functional requirements that specify what the product must do to deliver the defined value proposition. This section translates user needs and product vision into specific, testable requirements.
## Prerequisites
- Product vision and value proposition defined
- User personas and journeys completed
- Problem statement established
- Technical constraints understood
## Section Structure & Requirements
### 1. Requirements Overview
**Objective**: Provide high-level view of functional requirements
**Required Elements:**
- **Requirements Philosophy**: Approach to defining requirements
- **Scope Definition**: What's included and excluded from requirements
- **Requirement Categories**: How requirements are organized
- **Prioritization Framework**: How requirements are prioritized
- **Traceability Matrix**: How requirements trace to user needs and business goals
**Quality Criteria:**
- Clear scope boundaries established
- Prioritization framework is objective and consistent
- Requirements are traceable to user needs
- Organization facilitates understanding and implementation
**Template:**
[
## Functional Requirements Overview
### Requirements Philosophy
[Approach to defining and managing requirements]
### Scope Definition
**In Scope**: [What's included in this version]
**Out of Scope**: [What's explicitly excluded]
**Future Scope**: [What's planned for future versions]
### Requirement Categories
[How requirements are organized - by user type, feature area, etc.]
### Prioritization Framework
[How requirements are prioritized - MoSCoW, Kano, etc.]
### Traceability Matrix
[How requirements trace to user needs and business goals]
[
### 2. Core Functional Requirements
**Objective**: Define essential product capabilities
**Required Elements for Each Requirement:**
- **Requirement ID**: Unique identifier for tracking
- **Requirement Title**: Clear, descriptive title
- **User Story**: Requirement expressed as user story
- **Acceptance Criteria**: Specific, testable criteria
- **Priority Level**: Must-have, should-have, could-have, won't-have
- **User Persona**: Which personas this serves
- **Business Value**: Why this requirement matters
- **Dependencies**: Other requirements this depends on
- **Assumptions**: Assumptions underlying the requirement
**Quality Criteria:**
- Requirements are specific, measurable, and testable
- User stories follow standard format and are complete
- Acceptance criteria are unambiguous
- Priority levels are consistently applied
- Dependencies are accurately identified
**Template for Each Requirement:**
[
### [REQ-ID] [Requirement Title]
**User Story**: As a [user type], I want [functionality] so that [benefit].
**Acceptance Criteria**:
- [ ] [Specific, testable criterion 1]
- [ ] [Specific, testable criterion 2]
- [ ] [Specific, testable criterion 3]
**Priority**: [Must/Should/Could/Won't Have]
**User Persona**: [Primary persona this serves]
**Business Value**: [Why this requirement matters]
**Dependencies**: [Other requirements this depends on]
**Assumptions**: [Underlying assumptions]
**Effort Estimate**: [Development effort estimate]
[
### 3. Feature Specifications
**Objective**: Group requirements into coherent features
**Required Elements for Each Feature:**
- **Feature Overview**: Purpose and scope of feature
- **Feature Requirements**: All requirements that comprise the feature
- **Feature User Flows**: How users interact with the feature
- **Feature Dependencies**: Other features this depends on
- **Feature Success Metrics**: How feature success will be measured
- **Feature Risks**: Potential risks and mitigation strategies
**Template:**
[
## Feature: [Feature Name]
### Feature Overview
[Purpose and scope of feature]
### Feature Requirements
[List of all requirements that comprise this feature]
### User Flows
[How users interact with this feature]
### Dependencies
[Other features this depends on]
### Success Metrics
[How feature success will be measured]
### Risks and Mitigation
[Potential risks and mitigation strategies]
[
### 4. Integration Requirements
**Objective**: Define how product integrates with external systems
**Required Elements:**
- **Integration Overview**: Summary of all required integrations
- **API Requirements**: Specifications for APIs that must be consumed or provided
- **Data Exchange Requirements**: What data needs to be exchanged and how
- **Authentication Requirements**: How integrations will be secured
- **Performance Requirements**: Performance expectations for integrations
- **Error Handling Requirements**: How integration failures will be handled
### 5. Data Requirements
**Objective**: Specify data needs and management requirements
**Required Elements:**
- **Data Model**: Key data entities and relationships
- **Data Sources**: Where data comes from
- **Data Quality Requirements**: Standards for data accuracy and completeness
- **Data Retention Requirements**: How long data must be kept
- **Data Privacy Requirements**: Privacy and protection requirements
- **Data Migration Requirements**: How existing data will be migrated
### 6. Business Rules and Logic
**Objective**: Define business rules that govern product behavior
**Required Elements:**
- **Business Rules Catalog**: All business rules that apply
- **Rule Priorities**: How conflicting rules are resolved
- **Rule Exceptions**: When and how rules can be overridden
- **Rule Validation**: How rules are validated and enforced
- **Rule Changes**: How business rules can be modified
## Information Gathering Requirements
### Functional Context Needed:
- User workflows and processes
- Business rules and constraints
- Integration requirements and constraints
- Data requirements and sources
- Performance and scalability needs
### Validation Requirements:
- User validation of requirements and user stories
- Technical validation of feasibility
- Business validation of value and priority
- Stakeholder review and approval
## Cross-Reference Requirements
### Must Reference:
- User personas and their goals
- Product vision and value proposition
- Technical constraints and capabilities
- Business objectives and success criteria
### Must Support:
- Technical architecture decisions
- User experience design
- Testing and quality assurance plans
- Implementation planning and estimation
## Common Pitfalls to Avoid
### Requirements Definition Pitfalls:
- **Solution specification**: Specifying how instead of what
- **Requirement inflation**: Adding unnecessary complexity
- **Ambiguous language**: Using vague or interpretable terms
- **Missing edge cases**: Not considering error conditions and exceptions
### User Story Pitfalls:
- **Technical user stories**: Writing stories from system perspective
- **Epic user stories**: Stories that are too large to implement
- **Missing acceptance criteria**: Not defining how to test the story
- **Persona mismatch**: Stories that don't match defined personas
### Prioritization Pitfalls:
- **Everything is high priority**: Not making hard prioritization decisions
- **Feature bias**: Prioritizing features over user value
- **Technical debt ignorance**: Not accounting for technical requirements
- **Stakeholder politics**: Letting politics drive prioritization
## Edge Case Considerations
### When Requirements are Uncertain:
- Use assumption-driven development approach
- Plan for rapid validation and iteration
- Build flexibility into architecture
- Document uncertainty and validation plans
### When Users Have Conflicting Needs:
- Prioritize based on business value and user impact
- Consider configurable solutions
- Plan phased approach to address different needs
- Document trade-offs and decisions
### When Technical Constraints Limit Requirements:
- Work with technical team to understand constraints
- Identify alternative approaches to meet user needs
- Plan technical debt reduction to enable future requirements
- Document constraints and their impact
## Validation Checkpoints
### Before Finalizing Section:
- [ ] All requirements are specific, measurable, and testable
- [ ] User stories follow standard format and are complete
- [ ] Acceptance criteria are unambiguous and complete
- [ ] Priority levels are consistently applied
- [ ] Dependencies are accurately identified and documented
### Cross-Section Validation:
- [ ] Requirements support product vision and value proposition
- [ ] Requirements address identified user needs and pain points
- [ ] Requirements are technically feasible given constraints
- [ ] Requirements can be delivered within timeline and budget
- [ ] Requirements support defined success metrics
## Output Quality Standards
- Requirements are clear, complete, and unambiguous
- User stories are well-formed and testable
- Prioritization is objective and well-justified
- Dependencies and assumptions are clearly documented
- Content enables accurate estimation and planning