BillSensor

I got hit with a $209 charge from a SaaS tool I thought I'd cancelled months ago. No warning email. No reminder. Just gone from my account.

That made me angry enough to actually sit down and go through 62 popular SaaS tools and document exactly how each one handles cancellation. Not from their marketing pages. From the actual cancellation flows.

I scored each tool from 1 to 10 on how badly they treat you on the way out. Higher score = worse behavior.

What the score measures

Five things, specifically:

Can you cancel online, or do they force you onto a phone call or live chat? How many steps does it actually take? Do they show a fee screen designed to scare you back? Do they warn you before a free trial converts to paid? And do they keep charging after you've already cancelled?

The worst offenders (scores 8-10)

Adobe Creative Cloud — 9/10

The one everyone already knows about. Annual plan, cancellation fee up to 50% of the remaining contract value, buried inside a 4-step flow. A dedicated subreddit exists just to complain about this. r/FuckAdobe has 300,000+ members. That tells you everything.

SEMrush — 8/10

Multiple reports of users being charged $200+ after cancelling. The cancellation flow routes you through a retention gauntlet before you can confirm anything. One Reddit thread title sums it up: "SEMrush charged me $211 using deceptive dark patterns."

Mailchimp — 8/10

Users regularly report being charged months after closing their account. Support is hard to reach. The "pause" option gets pushed aggressively as an alternative to cancellation. Pausing resets nothing. The charge just comes back.

Zapier — 7/10

Annual plan auto-renews with no pre-renewal email. Downgrading to free is not the same as cancelling, and several users found out the hard way. They thought they were out. They weren't.

Notion — 7/10

Annual billing, no renewal reminder. Pro users consistently report being charged for a full year without any warning. Refund requests are handled case by case with no published policy.

What good actually looks like (scores 1-3)

A handful of tools get this right. Cancel button on the dashboard. One confirmation screen. No fee. No guilt trip. Confirmation email sent immediately.

These tools exist. They're just not the ones that dominate the market.

The tactics I kept seeing

Forced continuity. Free trial converts to an annual plan automatically. No reminder sent. You find out when the charge hits.

Confirmshaming. The "don't cancel" button says something like "No thanks, I don't want to save money." The whole point is to make you feel stupid for leaving.

Hidden cancel flow. The cancel option technically exists. You just have to go through account settings, then billing settings, then plan settings, then a chat widget. Every extra step is a dropout opportunity, and they know it.

Pause as misdirection. Support agents offer to pause your account instead of cancelling. The charge resumes automatically after the pause period. Most users never realise this until it's too late.

Post-cancellation charging. The worst one. You cancelled. You have the confirmation email. They charged you anyway, three months later.

Why the money is almost beside the point

The $209 I lost wasn't really the problem. The problem is that none of this is accidental. These patterns are deliberate. They're revenue strategy dressed up as UX. The harder it is to leave, the more people give up and stay.

And until recently, there was nothing watching for it on your behalf.

What I built because of it

I built BillSensor, a Chrome extension that passively detects SaaS billing emails as you use Gmail, alerts you 7 days before a renewal charge hits, and shows you the dark pattern score for every tool it finds.

No Gmail OAuth required. No bank connection. Nothing leaves your browser.

The full scored list of 62 tools is at https://billsensor.com/page/supported-tools.

If you've been hit by any of the tools above, or you know something about a specific cancellation flow that I missed, I'd like to hear it. The list gets updated as I find more.

BillSensor. Chrome Web Store: Add to Chrome

Status: Live on Chrome Web Store Installs: 42 Revenue: $0 Reviews: 6 x 5-star

Why I Built This

On May 11, 2026, I started building BillSensor. The trigger was a charge I didn't expect.

I had cancelled a popular design tool, got the confirmation email, and moved on. Then a charge appeared on my card for $209. Turned out I was on an "annual plan billed monthly": a contract structure that looks like a monthly subscription but exits like an annual one. The early termination fee was 50% of whatever was left on the year. It was disclosed somewhere in the sign-up flow, in a tooltip I had scrolled past.

Spent an hour on chat support getting it reversed. The reversal worked, but the experience stayed with me.

I started reading Trustpilot reviews for the tools in my stack. Then for tools my clients used. The same complaints kept appearing independently across dozens of different products. "Charged after cancelling." "No cancel button." "Renewed with no warning." A 2023 Stanford and Texas A&M study confirmed what I was seeing: subscriber inattention increases company revenue by between 14% and 200%, depending on the service. This isn't a side effect of subscription models. It's a design choice.

I decided to build something about it.

What BillSensor Does

BillSensor is a Chrome extension that detects SaaS billing emails and alerts users before renewal charges.

For Gmail users, it reads billing emails passively as they're opened, with no Google account connection, no OAuth permission, and no setup required. Install and it works immediately.

For Outlook and Microsoft 365 users, a one-time connected scan via the extension popup surfaces 12 months of billing history instantly.

The feature I'm most proud of: a dark pattern scoring system. Every detected subscription gets a score from 1 to 10 based on how aggressively that tool uses billing tactics: hidden cancellation fees, post-cancellation charges, silent plan upgrades, seat additions without consent. Adobe scores 9/10. DocuSign scores 9/10. Zapier scores 8/10. These aren't opinions. They're based on Trustpilot complaint data, Reddit thread analysis, and regulatory filings including two federal settlements closed in 2026.

No competitor currently offers this. Every other subscription tracker treats all tools as equal billing risks.

The Build: 2.5 Months, Solo

I'm an IIT grad based in Kolkata, India. This is my first consumer-facing product. I've been building software for clients for years. This is the first time I built something because a problem made me angry enough to fix it.

Tech stack:

• Chrome Extension Manifest V3, vanilla JavaScript

• Node.js + Express backend

• MySQL on Hostinger

• Paddle as payment processor and Merchant of Record

• Resend for transactional email

Key technical decisions:

The no-OAuth approach for Gmail was the most important architectural choice. Competitors like SaaS Subscription Tracker and CostLoop require Gmail OAuth, which triggers a "read and change your email" permission warning on install. That warning kills conversion. Passive DOM reading bypasses it entirely. The extension reads emails as users open them naturally, without any account connection.

The dark pattern scoring database required the most non-technical work. I spent several weeks going through Trustpilot reviews, Reddit threads, and regulatory filings to build credible scores for 62 tools. The Adobe and Shutterstock DOJ/FTC settlements were primary sources.

Payments through Paddle were a deliberate choice for an Indian-founded product selling internationally. Paddle acts as Merchant of Record, which handles global tax compliance automatically. No manual VAT, no GST complications.

Launch: What Happened in Week 1

Chrome Web Store: 42 installs, 6 five-star reviews. Majority of installs from the US.

Reddit: Posted a PSA on r/FuckAdobe about Adobe's cancellation fee and the DOJ settlement with no product mention in the post. 11,000 views in 24 hours, 1 comment. The username did the rest.

Blog: Published 4 posts targeting high-volume search queries. All indexed within 24 hours of publishing. Currently ranking at positions 4-15 across 64+ keywords. That surprised me. I expected organic search to take months.

Directories: Submitted to AlternativeTo, F6S, SaaSHub, G2, Capterra, GoodFirms, SoftwareSuggest, SpotSaaS, Future Tools, TechReviewer, and a few others. Most are pending approval or in queue.

Reviews: 6 five-star reviews. All from users I'd never interacted with. That felt better than the install count.

What Didn't Work

Reddit sitewide filter. The account got flagged after a few rapid posting attempts across subreddits. Every subsequent post, regardless of content, format, or links, gets auto-removed by Reddit's filter. Still working through this. r/StartUpIndia went through and got genuine engagement. r/SideProject has removed every attempt.

r/chrome_extensions. Posted there, it went live, got 130 views over 8 hours. The subreddit is 41K members but almost no engagement.

Where I Am Now

Pre-revenue. Zero paying users. 42 installs.

The next milestone is 100 installs before spending anything on paid acquisition or the CASA assessment required for Gmail bulk scan, which is the Pro feature that justifies the $9/month price point. The passive detection alone is genuinely useful. The goal is proving enough users agree before investing further.

What I think is working: The blog content strategy is producing results faster than expected. Ranking for "Adobe charged after cancelling subscription" and similar queries at position 4-15 in week 1 is ahead of what I planned. The dark pattern angle resonates. It gives the content a point of view that pure subscription tracking posts don't have.

What I'm unsure about: Free-to-paid conversion once I have more users. The free plan is deliberately generous: unlimited passive detection, no artificial caps on what you can detect. The bet is that seeing a dark pattern score of 9/10 next to an Adobe subscription, combined with a renewal alert 7 days before the charge, is enough of an "aha moment" to convert. I haven't been able to test this yet.

What's Next

• 100 installs

• First paying user

• Post-cancellation monitoring (Phase 2, no competitor has this)

• Outlook multi-account support

• Product Hunt launch (planning once reviews and install velocity are stronger)

Happy to answer questions about the build, the no-OAuth detection approach, the dark pattern scoring methodology, or anything else.

BillSensor. Chrome Web Store: Add to Chrome