Challenge
Deliver a comprehensive financial platform with real-time market data, advanced screening, and intelligent portfolio insights while respecting third-party rate limits and sustaining performance.
Solution
Built a production-ready SvelteKit application featuring multi-tier caching, AI-assisted research, and deep integrations with Polygon.io, Alpha Vantage, and Supabase for resilient market intelligence.
Technology Stack
Balanced tooling across frontend, backend, and AI layers keeps experiences fast and reliable.
Frontend Experience
- SvelteKit application architecture
- Tailwind CSS design system with custom theming
- TypeScript-first development
- TradingView widgets for rich charting
Backend & Data
- Supabase database and authentication
- PostgreSQL for persistent market datasets
- Polygon.io APIs for equities data
- Alpha Vantage APIs for insider intelligence
AI & Automation
- OpenAI-powered chatbot with function calling
- Schema-enforced structured outputs
- Node.js ingestion scripts for scheduled updates
- Automated data normalization pipelines
Core Features
From screening to analysis, every workflow is optimized for clarity, speed, and accuracy.
Advanced Stock Screener
High-performance filtering engine surfaces equities based on market capitalization, sector, and trading activity.
- Instant symbol search with exchange filtering
- Market cap and volume thresholds for precision
- Sector-based categorization and sorting controls
- Client-side optimizations for responsive interactions
- Polygon.io-backed datasets with graceful fallbacks
Technical Implementation
Reactive Svelte stores drive live filtering while Polygon.io responses are cached to minimize API calls without sacrificing responsiveness.
Interactive Financial Charts
TradingView charts visualize price action with configurable technical indicators and historical context.
- Real-time price streams with exchange code normalization
- Configurable indicators (20/50/200 MA, RSI, VWAP)
- Chart preferences centralized via `chartConfig.json`
- Historical end-of-day data overlays
- Consistent theming across detail pages
Configuration Management
A shared config object keeps indicator defaults synchronized while allowing per-user overrides when needed.
AI-Powered Financial Assistant
Conversational AI delivers context-aware recommendations backed by live data and portfolio intelligence.
- OpenAI function calling to fetch real-time fundamentals
- Structured JSON responses for deterministic rendering
- Dynamic follow-up prompts tailored to user queries
- Portfolio-aware analysis for personalized insights
- Secure tool invocations for company and portfolio data
Technical Architecture
GPT-4 leverages schema-enforced outputs and functions like `get_company_profile` and `get_user_portfolio` to enrich every response with live context.
Data Architecture & Performance
Smart caching and schema design keep market data fresh without exceeding provider limits.
Intelligent Caching Strategy
- Browser localStorage caches frequently accessed quotes
- Supabase persistence stores company profiles and history
- Rate-limit aware scheduling maintains Polygon.io compliance
- Supabase Storage hosts optimized company logos
Database Schema Highlights
- company_profiles table captures detailed metadata
- daily_stock_prices stores historical OHLC records
- short_interest_reports tracks bi-monthly disclosures
- insider_transactions monitors executive trades
- user_portfolios powers personalized tracking
Advanced Features
Supporting systems reinforce the core product with branding, automation, and security.
Company Branding System
- Local cache prioritized before remote lookups
- Supabase Storage fallback for persistent assets
- Server-side proxy bypasses CORS restrictions
- Automatic optimization ensures crisp rendering
Financial Ticker Component
- Fixed-position ticker surfaces saved companies
- Hydrates from cached Supabase price snapshots
- Responsive design spans desktop to mobile
- Graceful loading states for live updates
Data Ingestion Scripts
- Automated short interest and insider fetchers
- Company profile synchronization pipelines
- Rate-limit aware execution windows
- Robust error handling with logging
Authentication & Security
- Supabase Auth with server-rendered protections
- Row Level Security policies guard user data
- Per-user portfolio segregation and access control
- Secure handling of external API credentials
Key Achievements
Engineering rigor paired with product polish delivers a standout retail investing experience.
Technical Implementation
- Real-time screener with responsive filtering UX
- TradingView charts featuring configurable indicators
- AI chatbot combining live data and user context
- Sophisticated logo pipeline with multi-tier fallbacks
- Caching strategy blending client and server storage
Platform Features
- Live financial ticker available across the app
- Short interest and insider transaction analytics
- Supabase-authenticated user management
- Polygon.io rate-limit compliance baked in
- Automated ingestion scripts with observability
Technical Challenges & Solutions
Strategic engineering kept the platform compliant, consistent, and insightful.
API Rate Limiting
Challenge
Polygon.io’s five calls per minute limit demanded careful orchestration to keep experiences realtime without exhausting quotas.
Solution
Introduced tiered caching (localStorage, Supabase) combined with `ensureApiCallPermitted` guardrails to throttle requests intelligently.
CORS & Image Handling
Challenge
Browser restrictions blocked direct access to Polygon.io logos, risking inconsistent branding assets across the UI.
Solution
Implemented a server-side `/api/image-proxy` endpoint and persisted assets with `saveLogoToSupabaseStorage`, producing reliable, cached logos.
AI Context Management
Challenge
Maintaining meaningful AI responses while staying within context limits required balancing data richness with token budgets.
Solution
Adopted targeted function calls that fetch only what’s needed at runtime, ensuring concise yet informative GPT-4 answers.
Future Enhancements
A clear roadmap ensures the product continues to grow alongside investor needs.
Planned Features
- End-to-end portfolio management with P&L tracking
- Custom indicator builder for advanced charting
- Real-time price alerts and notification channels
- ETF holdings analysis and comparison tooling
- Paper trading simulator for strategy testing
Technical Improvements
- Expanded AI tooling for technical indicator insights
- WebSocket streaming for live market updates
- Mobile-first responsive refinements
- Comprehensive unit, integration, and E2E tests
- Observability for performance and reliability
Deployment & Infrastructure
Cloud-native operations streamline releases and keep data secure.
Hosting Platform
- SvelteKit deployed on Vercel with adapter-auto
- Automatic preview deployments for every PR
- Managed environment variables and secrets
- CI/CD pipeline delivering updates instantly
Database & Storage
- Supabase PostgreSQL backing application data
- Row Level Security policies safeguarding users
- Supabase Storage for company media assets
- Centralized schema migrations via SQL scripts
Development Workflow
- TypeScript-first codebase for safety
- Environment management across local and prod
- Local network access for device testing
- Modern tooling with linting and formatting