I created Duedrop, an easy reminder for freelancers about invoices. Where do I go wrong?

Duedrop was created after I tried to chase up a late invoice for the third time in a single month and having to rewrite the same awkward email every time. It simply reads a spreadsheet or CSV file, sends a friendly reminder, another one after two weeks and a final reminder which you approve yourself. No need to migrate from your existing accounting system.

The tech stack used is minimal. Next.js on the frontend, Supabase for storage and authentication, and a queue that sends out emails at the exact hour when the client responds. The trickiest part in this project wasn’t coding, but finding the right tone. The initial drafts were either too meek or aggressive and took six freelancers to come up with the perfect templates.

This is what I am unsure about. Is something like this worth paying for monthly, or is it a one-time deal? And would you use software to remind yourself to follow up with a client in your name?

Please don’t upvote me on this. I just want you to tell me where this falls apart for you. I will answer every comment.