Most IP-based fraud checks stop at geolocation and VPN flags. That misses a layer of context sitting right there in the data: the autonomous system number. A single ASN lookup tells you which organization controls the IP block your visitor is connecting from. It tells you whether that IP belongs to a residential ISP like Comcast (AS7922), a cloud provider like Hetzner (AS24940), or a VPN operator. That distinction matters. A login attempt from a Comcast residential IP and one from a Hetzner datacenter IP carry very different risk profiles, even if both geolocate to the same city. This tutorial builds a risk-scoring function that combines ASN type classification with IP security signals (VPN detection, proxy detection, threat scoring) in a single API call. You will walk away with Express middleware you can drop into a Node.js app, plus equivalent Python code.…