3D Secure (3DS) is a security protocol embedded in the online purchasing process to authenticate cardholders and reduce third-party credit card fraud, which is projected to reach $43 billion by 2026. The protocol involves three domains: the issuer, the acquirer, and the card network, each playing a role in verifying transactions. While the original 3DS required burdensome manual verification, the updated 3D Secure 2 (3DS 2.0) uses transaction data and device intelligence for most authentications, minimizing user involvement and potential transaction abandonment. Despite its benefits in fraud reduction and liability shift to the card issuer, 3DS can add costs and complexity for merchants, and its implementation varies globally, with mandatory compliance in regions like the European Economic Area and India. Device intelligence further optimizes the process by analyzing numerous data points to assess transaction trustworthiness, balancing security and convenience for merchants and shoppers alike.