Interceptive Middleware: Building a Data-Driven Permission Engine

One of the biggest challenges in building PawMate was creating a monetization model that wasn't hard-coded. We needed a way for business admins to toggle features like 'See Who Liked Me' or adjust daily swipe limits without a single line of code changes. Our solution was the Interceptive Middleware Architecture. Every request passing through our Express API is intercepted by a FeatureGate service. This service resolves the user's tier, fetches the associated permissions from a Redis-backed cache, and evaluates whether the action is permitted within their current quota. Using Redis ensures that even with hundreds of permission checks per second, we maintain sub-millisecond overhead. This approach has transformed how we manage platform scaling and product experimentation...