San Antonio, Texas
De’Mondre Zimmerman, also known as DJ, builds software for practical business workflows and studies systematic trading. He founded StopHarbor and Global Ticket Pay, and publishes independent research through Zimmër Trading. His work brings together product development, full-stack engineering, and careful measurement of what a system actually does.
StopHarbor is a route-planning workspace for small field teams. Office planners can bring addresses together, divide work across a crew, review itineraries, and share private route links. It is operated by GTP Systems Inc.
Visit StopHarbor →Global Ticket Pay is a traffic-citation lookup and payment service operated by GTP Systems Inc. It helps drivers search supported public court records in Texas, Georgia, and Alabama and choose payment assistance for eligible citations. It is a private service, not a court.
Visit Global Ticket Pay →Zimmër Trading is an independent research and software project. Zimmerman develops trading infrastructure and writes about execution, position sizing, accounting, and the evidence needed to evaluate a systematic strategy. The working papers describe their methods, assumptions, and limitations.
Explore Zimmër Trading →Working Paper 03, November 2, 2026. A reconstruction of live trading records, changing position sizes, and a drawdown, with a public market-level ledger and a replication package.
Working Paper 02, November 2, 2026. A study of position sizing, early-exit accounting, and modeled execution in a small live-trading sample.
Working Paper 01, September 21, 2026. A research agenda covering point-in-time data, energy fundamentals, realistic testing, and controlled execution.
Zimmerman is open to software engineering, technical sales, and research collaborations. Visit the homepage for his resume, browse all writing, or use the biography and media resources for introductions and interviews. Contact dj@globalticketpay.com.