BillSensor

BillSensor is a Chrome extension that monitors SaaS subscriptions and alerts users before renewal charges. It works with both Gmail and Outlook. For Outlook and Microsoft 365 users, connect once via the extension popup and BillSensor scans 12 months of billing history instantly, surfacing every active subscription including forgotten ones. For Gmail users, BillSensor reads billing emails passively as they are opened, with no Google account connection, no OAuth permission, and no setup required.

What distinguishes BillSensor from other subscription trackers is its dark pattern scoring system. Every detected subscription is rated from 1 to 10 based on how aggressively that SaaS tool uses billing dark patterns — hidden cancellation fees, post-cancellation charges, silent plan upgrades, and seat additions without consent.