Token billing is a metering model used by many AI services, where each input or output token is counted and converted into cost. A token is a chunk of text, so long prompts, verbose responses, retries, and multi-step agent workflows all increase usage. Unlike a flat subscription or simple VM charge, token billing ties spend directly to model activity.
In cyber security, this matters because cost can become a signal of abuse. Stolen API keys, bot-driven prompt flooding, runaway agent loops, and retry storms can burn through tokens quickly and reveal themselves as unusual usage patterns. Defenders use quotas, per-tenant limits, trace context, and anomaly detection to spot unexpected spikes and map them back to the responsible user, service, or workload. Good token billing visibility helps both finance and security identify misuse before it turns into a larger operational problem.