Aivora Gatekeeper is an AI billing firewall for OpenRouter-powered applications. It helps AI aggregators prevent unexpected API costs through usage quotas, workspace budget caps, cost estimation before requests, request-level gating, subscription-tier enforcement, and analytics. Built with FastAPI, Supabase, TypeScript, and OpenRouter, it adds a protection layer between users and AI providers to stop abuse, spam, and runaway API spending before costs occur.