Financial fraud detection is no longer about catching obvious anomalies after losses occur. As digital payments, lending, and financial services scale, fraud has become more targeted, subtle, and costly. This guide explores what financial fraud really looks like today, from identity misuse and transaction fraud to vendor and credit manipulation. It explains why legacy, rule-based controls struggle in modern environments and how businesses are shifting toward real-time, data-driven detection models. By combining behavioural signals, verification data, and machine learning, organisations can identify risk earlier without disrupting genuine users. The article also examines common challenges such as false positives, data silos, and evolving fraud patterns, and highlights how continuous monitoring and strong verification layers help build long-term resilience. Designed for businesses handling money or financial data, this guide offers a practical, grounded view of modern fraud detection.