About

Who builds this

Quartermaster is built and maintained by one person. Here is who, and why.

Hi, I'm Priyansh

I've been in crypto for 5+ years. I started back in 2020 and built a successful career in research, content and marketing. I'm an aspiring quantitative analyst who has already completed four core finance certifications. I'm also an aspiring software developer having learnt coding (CS50) myself (Python, C, Go). This app is a build-in-public tool to help you in your investing/trading journey.

Why I built Quartermaster

I always felt like an idiot reading and visualizing charts. After a couple of certifications hundreds of TA videos later, I realized that reading charts is not a skill. What matters is your ability to source, visualize, and understand the quantitative data. And hence: Quartermaster.

How it was built

Quartermaster is a build-in-public tool. Each feature will be shipped with the intention of making it quantitative data and analysis accessible to everyone. Quartermaster is currently free to use. The current version of the app features 4 tools.

  1. The OHLCV Downloader. A command-line script that queried Yahoo Finance, standardised the column names, and saved raw daily data to CSV.
  2. The Tick Inspector. A data-integrity layer that runs before any calculation: duplicate timestamps, missing calendar dates, negative volume, and corrupted price ticks such as a low above its own high.
  3. The Quant Analyzer. Daily and log returns, 20- and 50-day moving averages, rolling annualised volatility scaled for a 365-day market, cumulative return, and maximum drawdown.
  4. The web app. The three scripts were refactored into pure functions with no terminal input or output. Data now moves between them in memory as DataFrames, with a Streamlit interface and interactive Plotly charts on top.

What it is, and what it isn't

Quartermaster is a research tool. It downloads historical market data, refuses to analyse data that fails its integrity checks, and shows you what risk actually looked like over a period you choose — the volatility, the drawdowns, and the fat tails that summary statistics tend to hide.

Quartermaster is not a signal service, a backtester, a portfolio tracker, or a source of advice. It does not tell you what to buy. It does not predict anything. Every figure it shows describes the past.

It also is not a data vendor. Prices come from Yahoo Finance, a free and occasionally imperfect source. The limitations are documented in full, because a tool that hides its weaknesses is not worth trusting.

Built in the open

The methodology behind every number is published so you can check it, and the calculations are plain pandas and NumPy. Nothing proprietary, nothing hidden. If you find an error, please reach out.

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