BillSensor — Stop Surprise SaaS Charges

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BillSensor is a Chrome extension that monitors SaaS subscriptions and alerts you before renewal charges. It started as a personal project after getting hit by a hidden cancellation fee — the kind buried in fine print that most people don't notice until it appears on their bank statement.The core problem it solves: most SaaS tools don't send renewal reminders before charging you. A 2023 Stanford and Texas A&M study found that subscriber inattention increases company revenue by up to 200% depending on the service. The whole subscription model has a structural interest in you forgetting what you signed up for.BillSensor works differently depending on your email provider. For Gmail users, it reads billing emails passively as you open them — no Google account connection, no OAuth permission, no setup required. Install it and it works immediately. For Outlook and Microsoft 365 users, connect once via the extension popup and BillSensor scans 12 months of billing history instantly, surfacing every subscription including ones long forgotten.The feature that makes it different from every other subscription tracker is the 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. Adobe scores 9 out of 10. DocuSign scores 9 out of 10. Zapier scores 8 out of 10. The score appears next to every detected subscription alongside a direct cancel link, so you know which tools are most likely to make it hard to leave before you try to leave.No competitor currently offers dark pattern scoring. The closest alternatives — SaaS Subscription Tracker, CostLoop, Substash — require Gmail OAuth or bank account access and provide no information about the billing practices of the tools they track.Renewal alerts fire 7 days before each charge via Chrome notification on the free plan. Pro users also receive email alerts. No bank account or credit card connection is ever required. Email content never leaves your browser.The free plan includes unlimited passive detection, 7-day Chrome renewal alerts, dark pattern scores, and direct cancel links for the first 3 detected subscriptions. Pro is $9 per month and adds email alerts, cloud sync, cancellation records as PDF, and multiple Gmail account support. Team is $29 per month and adds shared dashboard and up to 10 members.Built solo. IIT Kharagpur grad, based in Kolkata, India. Currently at 15 installs with two 5-star reviews in the first week.