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Ticker Fintel

Stock Screener & Portfolio Tracker

A sophisticated browser-based financial platform built with modern web technologies, featuring real-time market data, AI-powered insights, and advanced portfolio management.

Project Overview

Challenge

Build a comprehensive financial platform that provides real-time market data, advanced screening capabilities, and intelligent portfolio tracking while managing API rate limits and ensuring optimal performance.

Solution

Developed a full-stack SvelteKit application with intelligent data caching, AI-powered chatbot integration, and sophisticated financial data processing using Polygon.io and Alpha Vantage APIs.

Technology Stack

Frontend

  • • SvelteKit (Framework)
  • • Tailwind CSS (Styling)
  • • TypeScript (Type Safety)
  • • TradingView Widgets (Charts)

Backend & Data

  • • Supabase (Database & Auth)
  • • PostgreSQL (Data Storage)
  • • Polygon.io API (Market Data)
  • • Alpha Vantage API (Insider Data)

AI & Automation

  • • OpenAI API (Chatbot)
  • • Function Calling (Dynamic Data)
  • • Structured Outputs (JSON Schema)
  • • Node.js Scripts (Data Ingestion)

Core Features

Advanced Stock Screener

Comprehensive screening system with real-time filtering capabilities:

  • • Symbol search and exchange filtering
  • • Market cap and volume filtering
  • • Sector-based categorization
  • • Sortable results table
  • • Client-side performance optimization

Technical Implementation

Built with SvelteKit's reactive stores for real-time filtering, utilizing Polygon.io API with intelligent caching to minimize API calls while maintaining responsive user experience.

Interactive Financial Charts

TradingView integration with sophisticated technical analysis:

  • • Real-time price charts
  • • Technical indicators (MA, RSI, VWAP)
  • • Configurable chart settings
  • • Exchange code mapping (XNAS → NASDAQ)
  • • Historical EOD data visualization

Configuration Management

Chart defaults managed via chartConfig.json, enabling consistent indicator sets (20/50/200d MA, RSI, VWAP) across all stock detail pages.

AI-Powered Financial Assistant

Advanced OpenAI integration with dynamic capabilities:

  • • Function calling for real-time data
  • • Structured JSON responses
  • • Context-aware financial analysis
  • • Interactive follow-up suggestions
  • • User portfolio integration

Technical Architecture

Uses GPT-4 with schema-enforced outputs and function calling to dynamically fetch company profiles and portfolio data, providing contextually relevant financial insights.

Data Architecture & Performance

Intelligent Caching Strategy

  • Local Storage: Browser-side caching for frequently accessed data
  • Supabase Persistence: Company profiles and historical data
  • API Rate Management: 5 calls/minute compliance with Polygon.io
  • Image Optimization: Company logos stored in Supabase Storage

Database Schema

  • company_profiles: Comprehensive stock metadata
  • daily_stock_prices: Historical pricing data
  • short_interest_reports: Bi-monthly short data
  • insider_transactions: Executive trading activity
  • user_portfolios: Personal investment tracking

Advanced Features

Company Branding System

Sophisticated logo handling with fallback strategies:

  • • Local storage cache priority
  • • Supabase storage integration
  • • Polygon API proxy for CORS handling
  • • Automatic image optimization

Financial Ticker Component

Real-time market data display across all pages:

  • • Fixed-position scrolling ticker
  • • Saved companies integration
  • • Cached price data from Supabase
  • • Responsive layout adaptation

Data Ingestion Scripts

Automated data collection and processing:

  • • Short interest data fetching
  • • Company profile synchronization
  • • Rate limit compliance
  • • Error handling and logging

Authentication & Security

Secure user management with Supabase Auth:

  • • Server-side rendering (SSR) auth
  • • Row Level Security (RLS) policies
  • • User-specific portfolio data
  • • Secure API key management

Key Achievements

Technical Implementation

  • • Comprehensive stock screener with real-time filtering
  • • Interactive TradingView charts with configurable technical indicators
  • • AI chatbot with OpenAI function calling and structured outputs
  • • Sophisticated company logo handling with fallback strategies
  • • Multi-tier caching system (localStorage + Supabase)

Platform Features

  • • Real-time financial ticker component
  • • Short interest and insider transaction data integration
  • • User authentication with Supabase Auth
  • • Rate limit compliance with Polygon.io API (5 calls/minute)
  • • Automated data ingestion scripts with error handling

Technical Challenges & Solutions

API Rate Limiting

Challenge

Polygon.io API limited to 5 calls/minute, requiring careful request management for real-time financial data access.

Solution

Implemented tiered caching with localStorage and Supabase persistence, plus ensureApiCallPermitted() function to manage rate limits.

CORS & Image Handling

Challenge

Browser CORS restrictions prevented direct image fetching from Polygon.io for company logos and branding assets.

Solution

Created /api/image-proxy server route to fetch images server-side, storing them in Supabase Storage with saveLogoToSupabaseStorage() function.

AI Context Management

Challenge

Balancing AI response quality with context size limits while providing relevant financial data for user queries.

Solution

Used OpenAI function calling with tools like get_company_profile() and get_user_portfolio() to fetch data dynamically as needed.

Future Enhancements

Planned Features

  • • Complete portfolio management with P&L tracking
  • • Advanced charting with custom technical indicators
  • • Price alerts and notification system
  • • ETF holdings analysis and comparison tools
  • • Paper trading simulation module

Technical Improvements

  • • Enhanced AI tools for technical indicator analysis
  • • Real-time WebSocket data streaming
  • • Mobile-responsive design optimization
  • • Comprehensive testing suite (unit, integration, E2E)
  • • Performance monitoring and analytics

Deployment & Infrastructure

Hosting Platform

Deployed on Vercel with automatic CI/CD

  • • SvelteKit with @sveltejs/adapter-auto
  • • Automatic preview deployments
  • • Environment variable management

Database & Storage

Supabase for all data persistence

  • • PostgreSQL database
  • • Row Level Security policies
  • • File storage for company assets

Development Workflow

Modern development practices

  • • TypeScript for type safety
  • • Environment configuration
  • • Local network development access