I kept losing to the same three players at my club
Every one of them had a pattern. The same opening every game, the same collapse under time pressure, the same reply when I pushed on the queenside. I could feel it, but I could not prove it.
So I wrote something that could. Chess Stalker is that tool. No company behind it, just one person who plays at your level.

The engineering
Systems engineering first, a software engineering degree on top of it. I wrote the analysis logic, the site and the database queries myself, so when something breaks there is nobody to wait for.
The security
It is why the site stores an email address and nothing else, why there is no search history tied to your name, and why payments never touch my servers.
The teaching
I trained as a secondary school teacher, and it changed how I built this. A number on its own teaches nothing, so every figure here comes with what to do about it on the board.
The chess
Club player, not a titled one. I say it because it matters: I built this for the rating range I actually play in, where preparation still decides games and nobody has a second to scout for them.
And what I will not claim
Three limits, stated before you pay for anything.
Write to me directly
There is no support team to route you through. The address below reaches me, and I answer my own mail.