justin@horn:~$ cat bio.txt
Justin Horn is a Philadelphia-based advanced privacy special operator working across open-source intelligence (OSINT), digital privacy, and civic technology: a generalist who investigates, builds the tools, and ships the result. He is the founder of ThumperSecure, the creator of 4philly.net, and a contributor to the OSINT Framework.
He has written software since 1993, when he started coding at age 13, and is self-taught. Today he works mainly in Python, Rust, and JavaScript, and he builds the collection and verification infrastructure he investigates with: crawlers, data pipelines, and automated monitors.
Before his work in security, Justin spent more than a decade (2005–2018) as a working DJ and emcee across Philadelphia and South Jersey, performing at weddings, bar and bat mitzvahs, and nightlife events. In 2012 he founded the entertainment agency 2LifeTalent.
His current work sits where public data, privacy, and accountability meet. Through ThumperSecure he publishes open-source privacy tools such as palm-tree and the Telespot family, and maintains a practical opt-out manual covering more than 400 data brokers. In civic technology he built 4philly.net and the phl-rental-license-log, which preserves rental-license history the city's own systems overwrite. After he found that the city's public systems did not show when a rental license had expired, he escalated it through a City Council office, and the city's GIS team confirmed the gap in writing.
He cares as much about evidence integrity as about collection. Records he publishes are kept in append-only, tamper-evident histories with SHA-256 hash manifests, and he uses AI-assisted development every day under one rule: generated code gets reviewed and tested, never trusted blind. His investigations rely on public sources only.
Justin works as an independent contractor and, since March 2025, as a legal marketing and SEO consultant for Kaplan & Kaplan. He is currently open to new clients and considering a full-time position. Outside work he has trained in Sin Moo Hapkido for 25 years.
Copy-ready versions
Justin Horn is a Philadelphia-based advanced privacy special operator working across OSINT, digital privacy, and civic technology, and the founder of ThumperSecure.
Justin Horn is a Philadelphia-based advanced privacy special operator working across open-source intelligence (OSINT), digital privacy, and civic technology. Self-taught and working as an independent contractor, he founded ThumperSecure, where he builds open-source investigation and privacy tools. He created 4philly.net, a free tool for checking Philadelphia rental licenses and violations, and contributes to the OSINT Framework. He has written software since 1993 and is open to new clients.
justin@horn:~$ ./contact --now