Why Notifio rates-limits by licence token, not IP address

Notifio is a desktop app that monitors rental listing pages and triggers server-side email alerts when new properties appear. The developer chose to rate-limit API requests by licence token rather than IP address, because multiple users in shared student housing or university networks often share a single IP. Under an IP-based limit, all housemates would compete for the same request budget, meaning legitimate users could have their alerts silently dropped. Using per-licence keys ensures every paying customer gets an independent allowance, which also aligns with what the rate limit is actually meant to control. The developer also namespaced rate-limit keys per endpoint to prevent licence validation calls from consuming the budget meant for notification delivery.