GEMonitor - OSRS Trading Terminal

Fintech Grade Grand Exchange Analytics Platform

A professional trading terminal for Old School RuneScape featuring realtime flip scanning, FIFO trade matching, portfolio tracking with unrealized P&L, session based analytics, social leaderboards, and 16+ money making calculators all wrapped in a mobile first, fintech inspired interface.

GEMonitor flip scanner interface showing sortable item grid with real time margins, ROI percentages, volume data, and advanced filtering controls in a dark fintech themed design

Project Overview

Role: Full-Stack Engineer

Duration: Ongoing (WIP)

Team: Solo Project

Year: 2025

MKV

Technologies Used

Next.js 16React 19TypeScriptTailwindSupabasePostgreSQLSWRLightweight ChartsLucide ReactOSRS Wiki API

Project Details

A production ready alternative to legacy OSRS trading tools like GE Tracker, built with modern web technologies to deliver superior UX and advanced analytics. GEMonitor combines real time Grand Exchange price data from the OSRS Wiki API with intelligent FIFO buy/sell matching algorithms, automatic 2 hour session grouping, portfolio tracking with costbasis analysis, and a comprehensive suite of calculators covering everything from High Alchemy to Herblore. The platform implements a freemium monetization model with Row Level Security policies in Supabase, planned RuneLite auto sync plugin integration, and social features including public profiles and four distinct leaderboard types all delivered through a responsive, TradingView inspired interface built with Next.js 16, React 19, and Tailwind.

Results & Impact

  1. FIFO algorithm

    That correctly pairs trades across partial fills and split orders

  2. Session detection

    Using timestamp gap analysis to auto-group trading periods

  3. Shared recipe schema powering 16 calculators

    With real time price injection

  4. Composite scoring formula weighting ROI

    Volume, buy limits, and margin stability

  5. OSRS Wiki API

    With SWR caching to respect rate limits while staying fresh

  6. Freemium access tiers

    Using Supabase Row Level Security policies

Challenge to Solution

  1. Challenge

    Build a competitive trading platform that matches feature parity with established tools while differentiating through superior mobile UX, advanced analytics, and social features.

    Implement complex FIFO matching logic for accurate profit tracking, design an intelligent flip scanner with probability weighting, create 16+ data driven calculators with real time price integration, build a scalable freemium architecture with Row Level Security, and deliver a professional fintech grade interface that works seamlessly across all devices all while using the same public price data as competitors.

  2. Solution

    Developed with Next.js 16 App Router leveraging server components for optimal performance, React 19 for concurrent features, and Supabase PostgreSQL implementing Row Level Security.

    Built intelligent FIFO algorithms that automatically pair buy/sell trades for accurate realized and unrealized P&L calculation. Implemented session based analytics that auto groups trades into 2 hour windows to identify performance patterns. Created an advanced flip scanner with multi dimensional filtering (ROI, volume, margins, buy limits) and probability weighted scoring. Designed 16+ calculators powered by static JSON recipe data and real time GE prices with 30 second ISR caching. Integrated OSRS Wiki API for 5 minute price updates, volume tracking, and historical timeseries. Built social features including opt in public profiles, four leaderboard types, and achievement badges. The platform is currently in WIP status with core features complete but payment integration and RuneLite plugin pending.

Product in Use

GEMonitor homepage showing overview of trading features and calculator tools
Modern landing page with fintech inspired design and feature overview
Advanced flip scanner showing sortable grid with margins, ROI, volume, and multi dimensional filtering
Flip scanner with probability weighted scoring and 8+ filter dimensions
Popular flips page displaying trending items with realtime margins and buy limits
Curated list of high volume flips with instant profit calculations and GE tax
Session analytics dashboard showing 2 hour grouped trades with performance insights
Automated session grouping identifying profit patterns and top performing items
TradingView style price chart with candlesticks and multiple timeframe options
Professional price charts with 5m/1h/6h/24h timeframes and volume tracking
Calculator suite showing Crafting calculator with sortable profit margins and GP/XP ratios
16+ money making calculators with real time GE prices updated every 5 minutes
Blog section with OSRS trading guides, tips, and market analysis articles
Educational content hub with trading strategies and skill training guides

Key Features

  1. Log trades

    And see profit/loss calculated automatically with GE tax

  2. View trading sessions grouped

    By time to spot your best hours

  3. Track portfolio value

    With per-item cost basis and performance

  4. Find flips

    Using scanner filters for margin, ROI, volume, and buy limits

  5. Calculate GP/hour

    For 16 skills with live prices

  6. Compare rankings on opt-in weekly

    And all time leaderboards

  7. Analyze price history

    With candlestick charts at multiple timeframes

  8. Set alerts

    For price movements on watched items

  9. Export trade history

    As CSV or JSON