Stopping Free Trial Abuse: Using ML to Flag Duplicate Accounts

cneuralnetwork · x · 2026-08-09

A developer shared engineering insights on preventing users from endlessly exploiting AI free trials with new accounts.

Problem: Simply blocking IPs hurts legitimate users sharing networks (like in hostels or cafes), and basic device fingerprinting is easily bypassed by switching browsers.
Solution: Shift the logic from asking 'is this the same user?' to 'how likely is this signup a duplicate?'
Implementation: Extract features like usage patterns, locations, IP reputation, and device similarity to train an XGboost model that calculates the probability of trial abuse. While not 100% foolproof, it significantly increases the cost for abusers to register.

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