Built a page monitoring tool after losing a deal to a competitor price drop I didn't know about; would love brutal feedback

Lost a deal a few months back that I really shouldn't have lost.

Competitor had quietly dropped their Pro price. No announcement and nothing on their socials; just a page that was different from the last time I'd looked at it. My prospect had already seen it and I found out mid-call.

So I went looking for something that would do it for me. Tried Visualping, tried Distill. They both work fine technically but the output is just raw diffs. Everything that changed. Copyright year, CSS file versions, actual pricing; all presented the same way and you still have to read through it to find the one line that matters.

I couldn't find anything that would just tell me what changed that I actually care about so I built it myself. I'm not technical at all - used Loveable to build it, which has been its own adventure.

It's called WhatChanged (https://whatchangedforme.com/). The basic idea is:

You paste in a URL: pricing page, API docs, etc... and optionally tell it what you care about. Something like "alert me if the enterprise tier price goes up" or "I need to know if rate limits change." Then it monitors the page on a schedule, strips out the noise (timestamps, CSS changes, copyright years, etc.), and when something changes it tells you what happened and why it matters specifically to you.

Here's an actual alert it generated recently from Stripe's pricing page:

"Pro plan increased £20 → £25/mo per seat. 25% price increase could add £50/mo to your team's bill. 14 cosmetic changes filtered out."

That's the whole thing. No diff. No noise.

It works on PDFs too - supplier contracts, insurance docs, etc. which I didn't originally plan but turns out people monitor a lot of non-webpage stuff.

Honest state of it right now: live, free tier available (3 monitors, weekly checks), Pro is £19/mo with daily checks and Slack integration. Zero paying users so far. Not sure if the pricing is right, not sure if I'm targeting the right people, not entirely sure the £19 number makes sense - I just picked something that felt reasonable (I think!).

A few things I'm genuinely unsure about and would love input on:

Does the "tell us why you care" personalisation thing actually sound useful or does it sound like a feature nobody will bother filling in? I go back and forth on this.

Is £19/mo the right ballpark? I've done zero research on this.

What pages are you actually manually checking right now that you wish you didn't have to?

If anyone wants to try it properly I'll give out free Pro access in exchange for honest feedback - not "looks great!" feedback, actually tell me what's broken or what you'd never pay for. Happy to be told it's rubbish if it helps me figure out where to take it.