8+ years of backend engineering experience with modern languages (Go, Java, Kotlin, Rust, etc.). 2+ years in a Staff+ role at a high-scale tech or fintech company. Deep knowledge of payments infrastructure (e.g., tokenization, card networks, ISO 8583, PCI). Strong background in event-driven systems, data consistency models, and system reliability. Ability to reason through complex distributed systems and make pragmatic trade-offs.