Ladder

Buy more of it when it costs less.

Rules

Anything less than the smaller drop counts as near the high.

Market data

Free at finnhub.io — 60 calls a minute, plenty for a handful of stocks. The key is stored on this device only.

Daily notification

Install Ladder to your home screen first — on iPhone, notifications only work once it's installed.

Generate notifier keys

Run once, then paste these into the worker's settings.

Figures are for your own bookkeeping, not advice. Data can lag the market.