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Product Requirements Document - Users & Features

4. User Personas & Use Cases

4.1 Primary Personas

Persona 1: "Novice Nina" - The Beginner Investor

Demographics

Age: 28
Occupation: Office worker
Income: ₩40M/year
Investment Experience: < 1 year
Investment Amount: ₩10M

Goals

Learn how to analyze stocks properly
Find stable, dividend-paying stocks
Avoid risky investments
Build long-term portfolio

Pain Points

Overwhelmed by financial jargon
Doesn't know which metrics matter
Scared of making mistakes
Needs guidance and education

Key Features Needed

Pre-built screening templates ("Stable Dividend Stocks")
Metric explanations and tooltips
Visual indicators (grades, scores)
Conservative filtering options

Success Scenario

Nina opens the platform, clicks "Dividend Stocks" template, sees 50 results sorted by dividend yield with A-grade financial stability. She clicks Samsung Electronics, sees clear financial charts with explanations, and feels confident adding it to her watchlist.

Persona 2: "Tactical Tom" - The Active Trader

Demographics

Age: 38
Occupation: Self-employed / Day trader
Income: ₩80M/year
Investment Experience: 5+ years
Investment Amount: ₩100M

Goals

Find short-term trading opportunities
Identify momentum stocks early
Track sector rotations
Maximize returns through active trading

Pain Points

Too slow to scan all stocks manually
Misses fast-moving opportunities
Needs real-time data
Wants customizable alerts

Key Features Needed

Real-time HOT stocks (volume surge detection)
Technical indicator filtering
Custom screening criteria
Price/volume alerts

Success Scenario

Tom checks "Today's Hot Stocks" at 10 AM, sees a biotech stock with 300% volume surge and breaking resistance. He filters for "Volume > 200%, Price Change > 5%, Market Cap < 500B" to find similar opportunities. Sets alert for stocks matching criteria.

Persona 3: "Value Victor" - The Fundamental Investor

Demographics

Age: 45
Occupation: Senior manager
Income: ₩120M/year
Investment Experience: 10+ years
Investment Amount: ₩300M

Goals

Find undervalued quality companies
Long-term wealth accumulation
Outperform index through stock-picking
Data-driven decision making

Pain Points

Time-consuming fundamental analysis
Difficult to compare across sectors
Needs comprehensive financial data
Wants backtest strategies

Key Features Needed

Advanced valuation filters (PER, PBR, EV/EBITDA)
Financial statement comparisons
Industry peer analysis
Quality metrics (ROE, profit margins)

Success Scenario

Victor creates a custom screen: "PER < 10, PBR < 1, ROE > 15%, Debt Ratio < 100%, Dividend Yield > 3%". Gets 15 results. Compares them side-by-side, exports to Excel for deeper analysis. Adds 3 stocks to his "Value Portfolio" for tracking.

4.2 User Journey Maps

Journey 1: First-Time Stock Screening

1. Landing Page
   → Sees "Find your next investment in 60 seconds"
   → Clicks "Start Screening"

2. Screening Interface
   → Presented with simple filters + templates
   → Selects "High Dividend Stocks" template
   → Adjusts dividend yield slider: > 4%

3. Results Display
   → 50 stocks appear instantly (< 500ms)
   → Sorted by dividend yield
   → Color-coded by financial grade

4. Stock Selection
   → Clicks on "KB Financial Group"
   → Sees detailed page with charts

5. Analysis
   → Reviews financial summary
   → Checks 5-year dividend history chart
   → Reads metric explanations

6. Action
   → Adds to "Watchlist"
   → (Optional) Creates account to save

Journey 2: Portfolio Tracking

1. Login
   → Navigates to "My Portfolio"

2. Portfolio Creation
   → Clicks "New Portfolio"
   → Names it "Growth Portfolio"

3. Adding Holdings
   → Searches "Samsung Electronics"
   → Enters: 10 shares @ ₩70,000

4. Performance Monitoring
   → Dashboard shows: +5.2% gain
   → Sees daily P&L chart
   → Compares vs KOSPI index

5. Rebalancing Decision
   → One stock down 15%
   → Uses screener to find replacement
   → Updates portfolio

4.3 Use Cases

UC-001: Basic Stock Screening

Actor: Any user (guest or registered)

Precondition: User is on the main screening page

Main Flow:

User selects market (KOSPI/KOSDAQ/All)
User applies filters:
- Valuation: PER < 15
- Growth: Revenue Growth > 10%
- Size: Market Cap > ₩1T
System queries database
System returns filtered results in < 500ms
User sees list of matching stocks with key metrics

Postcondition: Results are displayed with option to refine filters

Alternative Flows:

2a: User selects pre-built template instead
4a: No results found → System suggests relaxing filters

UC-002: Stock Detail Analysis

Actor: Registered user

Precondition: User has selected a stock from screening results

Main Flow:

System loads stock detail page
System displays:
- Price chart (1D, 1W, 1M, 3M, 6M, 1Y, 5Y views)
- Financial summary (revenue, profit, margins)
- Valuation metrics (PER, PBR, PSR, etc.)
- Growth indicators
- Financial statements (5 years)
User switches between tabs (Overview, Financials, Valuation, etc.)
User hovers over metrics to see explanations
User clicks "Add to Watchlist"

Postcondition: Stock is saved to user's watchlist

Alternative Flows:

5a: User not logged in → Prompted to login/register

UC-003: Real-time Hot Stock Detection

Actor: System (automated) + Any user

Precondition: Market is open

Main Flow:

System monitors trading volume every 5 minutes
System detects stocks with volume > 150% of 20-day average
System calculates price momentum
System ranks by combined volume + momentum score
System updates "Today's Hot Stocks" section
User visits homepage, sees updated hot stocks
User clicks on a hot stock to investigate

Postcondition: User discovers trending opportunities

Business Rule: Only update during market hours (09:00-15:30 KST)

UC-004: Portfolio Performance Tracking

Actor: Registered user (Premium tier)

Precondition: User has created at least one portfolio

Main Flow:

User navigates to "My Portfolio"
System calculates current portfolio value
System computes:
- Total gain/loss (KRW and %)
- Daily change
- Performance vs KOSPI index
System displays:
- Holdings table (stock, shares, avg cost, current price, P&L)
- Performance chart over time
- Asset allocation pie chart
User clicks "Add Holding"
User searches for stock and enters purchase details
System updates portfolio calculations

Postcondition: Portfolio reflects new holdings

UC-005: Custom Alert Creation

Actor: Registered user (Premium tier)

Precondition: User is viewing a stock detail page

Main Flow:

User clicks "Create Alert" button
System shows alert creation modal
User configures alert:
- Type: Price Alert
- Condition: "Price rises above ₩75,000"
- Notification: Email + Push
User saves alert
System monitors stock price continuously
When condition met, system triggers notification
User receives email: "Alert triggered for Samsung Electronics"

Postcondition: Alert is active and monitoring

Business Rule: Free users: 3 alerts max, Premium: Unlimited

5. Feature Requirements

5.1 Feature Prioritization Framework

Priority Levels:

P0 (Must-Have): Core functionality, product unusable without it
P1 (High): Critical for competitive advantage
P2 (Medium): Enhances user experience
P3 (Low): Nice to have, future consideration

5.2 Functional Requirements

FR-1: Stock Screening Engine

Priority: P0

Description: Core filtering system enabling users to discover stocks matching custom criteria.

Requirements:

ID	Requirement	Priority	Acceptance Criteria
FR-1.1	Support filtering by 200+ indicators	P0	All indicators from data spec available
FR-1.2	Multi-dimensional filtering (AND/OR logic)	P0	Users can combine ≥10 filters simultaneously
FR-1.3	Range-based filters (min/max)	P0	All numeric filters support min/max values
FR-1.4	Real-time query execution	P0	Results returned in < 500ms (p99)
FR-1.5	Result sorting (any column)	P0	Click column header to sort asc/desc
FR-1.6	Result pagination	P1	Show 50 results per page
FR-1.7	Export results to CSV/Excel	P2	Download button exports current view
FR-1.8	Save custom screens	P1	Registered users can save filter combinations
FR-1.9	Pre-built templates	P1	≥10 templates (dividend, growth, value, etc.)
FR-1.10	Market selection (KOSPI/KOSDAQ/All)	P0	Toggle to filter by market

User Stories:

As a value investor, I want to filter stocks with PER < 10 AND PBR < 1 AND ROE > 15%, so that I can find undervalued quality companies
As a beginner, I want to use a "High Dividend" template, so that I don't have to understand complex filters
As an active trader, I want to save my custom screens, so that I can reuse them daily

FR-2: Stock Detail Page

Priority: P0

Description: Comprehensive analysis view for individual stocks.

Requirements:

ID	Requirement	Priority	Acceptance Criteria
FR-2.1	Price chart with multiple timeframes	P0	Support 1D, 1W, 1M, 3M, 6M, 1Y, 5Y views
FR-2.2	Real-time price updates	P1	Update price every 30 seconds during market hours
FR-2.3	Financial summary dashboard	P0	Display revenue, profit, margins, ROE
FR-2.4	Valuation metrics section	P0	Show PER, PBR, PSR, PCR, EV/EBITDA, etc.
FR-2.5	Financial statements (5 years)	P0	Income statement, balance sheet, cash flow
FR-2.6	Quarterly & annual data toggle	P1	Switch between quarterly/annual view
FR-2.7	Peer comparison	P2	Compare with industry average + top 3 competitors
FR-2.8	Metric explanations (tooltips)	P1	Hover over metric name to see explanation
FR-2.9	Add to watchlist button	P1	One-click to add/remove from watchlist
FR-2.10	Historical dividend data	P1	Chart + table of dividend history

User Stories:

As an investor, I want to see 5 years of financial statements, so that I can identify trends
As a beginner, I want metric explanations, so that I can learn what PER means
As an analyst, I want to compare a stock with its peers, so that I can assess relative valuation

FR-3: Real-time Market Insights

Priority: P1

Description: Dynamic sections highlighting market trends and opportunities.

Requirements:

ID	Requirement	Priority	Acceptance Criteria
FR-3.1	Today's hot stocks (volume surge)	P1	Top 20 stocks with volume > 150% of 20D avg
FR-3.2	Top gainers/losers	P1	Top 20 by % price change today
FR-3.3	Sector performance heatmap	P2	Color-coded grid of 10 sectors with % change
FR-3.4	Rising/falling themes	P1	Identify trending investment themes
FR-3.5	Market overview dashboard	P1	KOSPI/KOSDAQ index, volume, top news
FR-3.6	Update frequency	P1	Refresh every 5 minutes during market hours
FR-3.7	Historical comparison	P2	Compare today's movers vs yesterday

User Stories:

As an active trader, I want to see volume surge stocks, so that I can identify momentum opportunities
As a thematic investor, I want to see rising themes, so that I can ride sector rotations

FR-4: Portfolio Management

Priority: P1

Description: Track and analyze personal stock holdings.

Requirements:

ID	Requirement	Priority	Acceptance Criteria
FR-4.1	Create multiple portfolios	P1	Users can create ≥5 separate portfolios
FR-4.2	Add/edit/delete holdings	P1	Enter stock, shares, purchase price, date
FR-4.3	Real-time portfolio valuation	P1	Calculate current value using live prices
FR-4.4	Gain/loss tracking (absolute & %)	P1	Show unrealized P&L per holding and total
FR-4.5	Performance vs benchmark	P1	Compare portfolio return vs KOSPI index
FR-4.6	Asset allocation visualization	P2	Pie chart by stock, sector, or market cap
FR-4.7	Transaction history	P2	Log of all buy/sell transactions
FR-4.8	Export portfolio to Excel	P2	Download current holdings + performance
FR-4.9	Dividend tracking	P2	Record received dividends, calculate yield
FR-4.10	Portfolio sharing (optional)	P3	Generate shareable link to portfolio

User Stories:

As an investor, I want to track my holdings in one place, so that I can monitor performance easily
As a long-term investor, I want to see my performance vs KOSPI, so that I know if I'm outperforming

FR-5: User Account & Authentication

Priority: P0

Description: Secure user registration and authentication system.

Requirements:

ID	Requirement	Priority	Acceptance Criteria
FR-5.1	Email + password registration	P0	Users can sign up with email
FR-5.2	Email verification	P0	Send verification link to confirm email
FR-5.3	Login with email/password	P0	Authenticate users securely
FR-5.4	OAuth login (Google, Kakao, Naver)	P1	Support social login for convenience
FR-5.5	Password reset flow	P0	Email-based password recovery
FR-5.6	Session management	P0	Secure JWT-based sessions with refresh tokens
FR-5.7	User profile management	P1	Edit name, email, password, preferences
FR-5.8	Subscription tier display	P1	Show current plan (Free/Basic/Pro)
FR-5.9	Account deletion	P2	Users can request account deletion (GDPR)
FR-5.10	Two-factor authentication (2FA)	P3	Optional 2FA via SMS/authenticator app

User Stories:

As a new user, I want to sign up with my email, so that I can save my preferences
As a busy user, I want to login with Kakao, so that I don't have to remember another password

FR-6: Search & Discovery

Priority: P1

Description: Quick search functionality to find stocks.

Requirements:

ID	Requirement	Priority	Acceptance Criteria
FR-6.1	Search by stock name (Korean)	P1	Autocomplete suggestions as user types
FR-6.2	Search by stock code	P1	Support 6-digit KOSPI/KOSDAQ codes
FR-6.3	Search autocomplete	P1	Show top 10 matches in dropdown
FR-6.4	Recent searches	P2	Show last 5 searched stocks
FR-6.5	Popular stocks section	P2	Display 10 most-viewed stocks today
FR-6.6	Search performance	P1	Return autocomplete results in < 100ms

User Stories:

As a user, I want to quickly search "삼성전자" and jump to its detail page
As a researcher, I want autocomplete to suggest stocks as I type, saving me time

FR-7: Alerts & Notifications

Priority: P2

Description: Customizable alerts for price movements and screening results.

Requirements:

ID	Requirement	Priority	Acceptance Criteria
FR-7.1	Price alerts (above/below threshold)	P2	Trigger when stock crosses specified price
FR-7.2	Volume surge alerts	P2	Notify when volume > X% of average
FR-7.3	Screening result alerts	P2	Notify when new stocks match saved screen
FR-7.4	Email notifications	P2	Send alert via email
FR-7.5	Push notifications (web)	P2	Browser push notifications
FR-7.6	Alert management dashboard	P2	View/edit/delete all active alerts
FR-7.7	Alert frequency limits	P2	Max 1 notification per hour per alert
FR-7.8	Free tier limits	P2	Free: 3 alerts, Basic: 10, Pro: Unlimited

User Stories:

As a trader, I want to be notified when Samsung crosses ₩80,000, so I can act quickly
As a screener user, I want daily alerts when new stocks match my "Value" screen

FR-8: Data Visualization

Priority: P1

Description: Charts and visual representations of financial data.

Requirements:

ID	Requirement	Priority	Acceptance Criteria
FR-8.1	Interactive price charts	P1	Zoom, pan, crosshair on charts
FR-8.2	Chart indicators (MA, volume)	P2	Overlay moving averages, volume bars
FR-8.3	Financial statement charts	P1	Bar charts for revenue, profit over time
FR-8.4	Comparison charts	P2	Overlay multiple stocks on one chart
FR-8.5	Responsive design	P1	Charts adapt to mobile/tablet/desktop
FR-8.6	Chart export (image)	P3	Download chart as PNG
FR-8.7	Performance optimization	P1	Render charts with 5 years data in < 1s

FR-9: Educational Content

Priority: P2

Description: Help users understand financial concepts.

Requirements:

ID	Requirement	Priority	Acceptance Criteria
FR-9.1	Metric glossary	P2	Explain 200+ indicators in simple Korean
FR-9.2	Tutorial videos	P2	≥10 video guides (screening, analysis, etc.)
FR-9.3	Blog articles	P2	Weekly investment insights and tips
FR-9.4	Contextual help	P1	"?" icon next to complex features
FR-9.5	Onboarding flow	P1	3-step interactive tutorial for new users

FR-10: Subscription & Billing

Priority: P1

Description: Tiered subscription plans with payment processing.

Requirements:

ID	Requirement	Priority	Acceptance Criteria
FR-10.1	Three-tier pricing (Free/Basic/Pro)	P1	Clearly differentiated feature access
FR-10.2	Payment processing	P1	Support credit card, bank transfer, Kakao Pay
FR-10.3	Subscription upgrade/downgrade	P1	Users can change plans mid-cycle
FR-10.4	Billing history	P1	Show past invoices and receipts
FR-10.5	Auto-renewal	P1	Automatically charge monthly/yearly
FR-10.6	Cancellation flow	P1	Users can cancel anytime (no refund pro-rata)
FR-10.7	Free trial	P1	14-day free trial of Pro tier

Pricing Tiers (Draft):

Feature	Free	Basic (₩9,900/mo)	Pro (₩29,900/mo)
Stock screening	✓ (10 filters)	✓ (Unlimited)	✓ (Unlimited)
Stock detail pages	✓	✓	✓
Historical data	1 year	5 years	10 years
Portfolios	1 portfolio	3 portfolios	Unlimited
Alerts	3 alerts	10 alerts	Unlimited
Export data	✗	✓ CSV	✓ Excel + API
Real-time updates	✗ (20 min delay)	✓	✓
Peer comparison	✗	✓	✓
API access	✗	✗	✓

5.3 Non-Functional Requirements

NFR-1: Performance

ID	Requirement	Target	Measurement
NFR-1.1	Screening query response time	< 500ms (p99)	Application Performance Monitoring (APM)
NFR-1.2	Stock detail page load time	< 1.5s (p95)	Real User Monitoring (RUM)
NFR-1.3	API endpoint response time	< 200ms (p95)	APM
NFR-1.4	Chart rendering time	< 1s for 5 years data	Frontend profiling
NFR-1.5	Search autocomplete latency	< 100ms	Frontend metrics
NFR-1.6	Database query optimization	No query > 1s	Slow query log

NFR-2: Scalability

ID	Requirement	Target	Measurement
NFR-2.1	Concurrent users	Support 10,000+ simultaneously	Load testing
NFR-2.2	Database scalability	Handle 2,400 stocks × 200 indicators = 480K metrics	Database monitoring
NFR-2.3	Horizontal scaling	Auto-scale API servers based on CPU > 70%	Kubernetes HPA
NFR-2.4	Cache hit rate	> 80% for frequently accessed data	Redis monitoring
NFR-2.5	CDN coverage	Serve static assets via CDN	CDN analytics

NFR-3: Reliability

ID	Requirement	Target	Measurement
NFR-3.1	System uptime	99.9% (< 8.76 hours downtime/year)	Uptime monitoring
NFR-3.2	Error rate	< 0.1% of all requests	Error tracking (Sentry)
NFR-3.3	Database backup	Daily backups, 30-day retention	Backup logs
NFR-3.4	Disaster recovery	RTO < 4 hours, RPO < 1 hour	DR drills
NFR-3.5	Health checks	All services report health status	Health endpoint monitoring

NFR-4: Security

ID	Requirement	Target	Measurement
NFR-4.1	Authentication	Secure JWT with refresh tokens, 15min expiry	Security audit
NFR-4.2	Password storage	Bcrypt with salt, min cost factor 12	Code review
NFR-4.3	HTTPS only	All traffic over TLS 1.3	SSL Labs scan
NFR-4.4	API rate limiting	100 req/min per user, 1000 req/min per IP	Rate limiter logs
NFR-4.5	SQL injection prevention	Parameterized queries, ORM usage	Security testing
NFR-4.6	XSS prevention	Content Security Policy, sanitized inputs	Security headers check
NFR-4.7	Sensitive data encryption	Encrypt PII at rest (AES-256)	Compliance audit
NFR-4.8	Vulnerability scanning	Weekly automated scans	Dependency checker

NFR-5: Usability

ID	Requirement	Target	Measurement
NFR-5.1	Mobile responsiveness	Support screens ≥ 360px width	Device testing
NFR-5.2	Browser compatibility	Support Chrome, Safari, Edge, Firefox (latest 2 versions)	Cross-browser testing
NFR-5.3	Accessibility	WCAG 2.1 Level AA compliance	Accessibility audit
NFR-5.4	Page load performance	Lighthouse score > 90	Lighthouse CI
NFR-5.5	Internationalization	Korean language, KRW currency	i18n framework

NFR-6: Data Quality

ID	Requirement	Target	Measurement
NFR-6.1	Data accuracy	99.9% match with official sources (KRX)	Automated validation
NFR-6.2	Data freshness	Update daily prices within 30 min of market close	Pipeline monitoring
NFR-6.3	Data completeness	< 0.1% missing data points	Data quality checks
NFR-6.4	Historical data integrity	No retroactive changes without audit log	Change tracking

NFR-7: Maintainability

ID	Requirement	Target	Measurement
NFR-7.1	Code coverage	> 80% unit test coverage	Coverage reports
NFR-7.2	Documentation	All APIs documented (OpenAPI spec)	Documentation review
NFR-7.3	Code quality	SonarQube quality gate pass	Static analysis
NFR-7.4	Deployment frequency	Support daily deployments	CI/CD metrics
NFR-7.5	Rollback capability	Rollback to previous version in < 5 min	Deployment testing

NFR-8: Compliance

ID	Requirement	Target	Measurement
NFR-8.1	Data licensing	Proper attribution for KRX/F&Guide data	Legal review
NFR-8.2	Investment disclaimer	Display on all pages with financial data	Compliance checklist
NFR-8.3	Privacy policy	GDPR/PIPA compliant	Legal review
NFR-8.4	Terms of service	Clearly stated user agreement	Legal review
NFR-8.5	Cookie consent	EU Cookie Law compliance (if applicable)	Cookie banner implementation

4. User Personas & Use Cases​

4.1 Primary Personas​

Persona 1: "Novice Nina" - The Beginner Investor​

Persona 2: "Tactical Tom" - The Active Trader​

Persona 3: "Value Victor" - The Fundamental Investor​

4.2 User Journey Maps​

Journey 1: First-Time Stock Screening​

Journey 2: Portfolio Tracking​

4.3 Use Cases​

UC-001: Basic Stock Screening​

UC-002: Stock Detail Analysis​

UC-003: Real-time Hot Stock Detection​

UC-004: Portfolio Performance Tracking​

UC-005: Custom Alert Creation​

5. Feature Requirements​

5.1 Feature Prioritization Framework​

5.2 Functional Requirements​

FR-1: Stock Screening Engine​

FR-2: Stock Detail Page​

FR-3: Real-time Market Insights​

FR-4: Portfolio Management​

FR-5: User Account & Authentication​

FR-6: Search & Discovery​

FR-7: Alerts & Notifications​

FR-8: Data Visualization​

FR-9: Educational Content​

FR-10: Subscription & Billing​

5.3 Non-Functional Requirements​

NFR-1: Performance​

NFR-2: Scalability​

NFR-3: Reliability​

NFR-4: Security​

NFR-5: Usability​

NFR-6: Data Quality​

NFR-7: Maintainability​

NFR-8: Compliance​

4. User Personas & Use Cases

4.1 Primary Personas

Persona 1: "Novice Nina" - The Beginner Investor

Persona 2: "Tactical Tom" - The Active Trader

Persona 3: "Value Victor" - The Fundamental Investor

4.2 User Journey Maps

Journey 1: First-Time Stock Screening

Journey 2: Portfolio Tracking

4.3 Use Cases

UC-001: Basic Stock Screening

UC-002: Stock Detail Analysis

UC-003: Real-time Hot Stock Detection

UC-004: Portfolio Performance Tracking

UC-005: Custom Alert Creation

5. Feature Requirements

5.1 Feature Prioritization Framework

5.2 Functional Requirements

FR-1: Stock Screening Engine

FR-2: Stock Detail Page

FR-3: Real-time Market Insights

FR-4: Portfolio Management

FR-5: User Account & Authentication

FR-6: Search & Discovery

FR-7: Alerts & Notifications

FR-8: Data Visualization

FR-9: Educational Content

FR-10: Subscription & Billing

5.3 Non-Functional Requirements

NFR-1: Performance

NFR-2: Scalability

NFR-3: Reliability

NFR-4: Security

NFR-5: Usability

NFR-6: Data Quality

NFR-7: Maintainability

NFR-8: Compliance