TrialKillar 🔪

Inspiration

A friend of mine had signed up for so many free trials at once, Netflix, Adobe, Spotify, LinkedIn, Notion, and a bunch of others. When it came time to cancel them all she was so annoyed having to go into each one, find the settings, click through all the cancellation screens and deal with all the "are you sure you want to cancel" popups. And on top of that she still missed a couple and got charged anyway. That conversation is what made me want to build this. Nobody should have to go through that process manually for every single service they tried. TrialKillar just does it for you.

What It Does

TrialKillar scans your Gmail for free trial emails, shows you everything that's about to charge you, and cancels them automatically using Amazon Nova Act before the billing date hits.

• Scans your inbox and detects active free trials
• Shows a dashboard with all your trials and how many days you have left
• Uses Amazon Nova Act to open the cancellation page and cancel for you
• Schedules auto-cancellations 24 hours before you get charged

How I Built It

I built the frontend in plain HTML and JavaScript, and the backend in Python using FastAPI. For the database I used SQLite so anyone can run it locally without needing any cloud setup. The Gmail API handles inbox scanning and I wrote a regex-based parser to pull out trial details like expiry dates and prices from emails. The Nova Act agent is fully built and lives in its own module, it just needs the API key to go live.

Challenges

Getting Nova Act API access was the biggest blocker. I applied during the hackathon but the credits didn't come through in time for the deadline. The integration is fully written and the app automatically switches to Nova Act the moment the key is added, but I wasn't able to demo it live.

I also had no access to AWS or any AI APIs so I had to get creative. I replaced DynamoDB with SQLite and built the email parser using regex instead of a language model. It actually works really well for detecting trials from known services like Netflix, Adobe, Spotify and LinkedIn.

What I Learned

I learned a lot about how Nova Act works differently from tools like Selenium. It understands pages visually which makes it much better for navigating real cancellation flows that change all the time. I also learned how to build a system that works even when the main API is not available yet.

What's Next

Once I get Nova Act access the full browser automation goes live. After that I want to add a browser extension that detects trials the moment you sign up, and mobile notifications so you get a heads up before anything gets cancelled.

Built With

• amazon-nova-act
• css
• fastapi
• gmail-api
• google-oauth
• html
• javascript
• python
• sqlite