Own device fingerprinting end-to-end: design client-side signal collection in browsers, build server-side matching and clustering algorithms robust to drift and adversarial manipulation, measure fingerprint quality and stability, detect manipulated fingerprints, and ensure performant, resilient production systems.

Design and operate real-time bot and fraud detection systems that are maintainable, observable, low-latency, and robust to adversarial change. Prioritize clarity, reduce rule sprawl, balance ML and deterministic approaches, and minimize false positives while handling high-volume traffic.

Own and evolve Castle's iOS and Android SDKs. Design SDK architecture and APIs, collect reliable device and behavioral signals, maintain performance and stability, manage builds/CI/CD, and ensure resilience against tampering across many devices and OS versions.