Nelson Koskela
Software engineer based in Houston, TX. I spent four years building trading tools and data-pipeline systems at JPMorgan Chase, and side projects like this one because I can't quite stop.
By the numbers
Where it started
Classical voice, minor in jazz, before pursuing computer science.
Washington, DC. Initially attended before transferring.
B.S. Computer Science.
Featured projects
These run against live data and real infrastructure. No mock backends.
Pipeline World
Submit a character and watch it move through a real queued pipeline (validate, test, build, deploy) in a top-down world. Every run is logged and queryable on the analytics page.
Open
Market Data Warehouse
yfinance's full price/dividend/split history pulled through an idempotent ingestion job into a dbt dimensional warehouse: a fact-table family (price, technical indicators, risk metrics) sharing conformed dimensions, plus a clearly labeled (not financial advice) trend projection. This page queries the built warehouse live, with a timeframe picker. Same dbt code runs on DuckDB, MotherDuck's free tier, or Snowflake.
Open
AI Assistant
A retrieval-grounded agent, not a scripted chatbot: a LangGraph agent loop decides for itself which tools to call and in what order, pulling real data from this site's own live projects (trading simulator, pipeline world, company scorer, timed-squares) instead of describing them from memory. Its flagship example chains three tool calls on its own -- a stock quote, a trend projection, then a written risk report -- deciding at each step what to call next based on what the last one returned. Retrieval runs over a pgvector store with local embeddings; generation is Groq, behind a rate-limited, prompt-injection-aware public endpoint. A stats page tracks tone, volume, and top questions from the logs, with no model calls.
OpenExperience
Data / quant engineering
Built Company Scorer's valuation, leverage, growth and profitability scoring off SEC EDGAR filings and market data, with a backtest module to check whether the score actually predicted anything.
Backend / infra engineer
Built Pipeline World's queued processing pipeline on RQ + Redis, with Postgres holding full run history and window-function analytics over every character that's gone through it.
Frontend / game logic
Built Timed-Squares' turn-based survival loop and public leaderboard in vanilla JS and HTML5 Canvas. No game framework.