Trade on rules, not on feel.
Build your own trading rules and test them on real history — in minutes.
How do you want to trade?
No code · Free to start · Claude Opus 5.5 or GPT-6 Astra
Not sure yet? Ask about any stock.
Real prices and filings — every number dated and sourced.
- Real prices · daily closes from Financial Modeling Prep
- No look-ahead · each day sees only its past
- Honest comparisons · every test sits next to just holding
- Your system watches · we email you the moment it signals
Who's behind it: Built by founder Yusen Lin at Plutux Technology Limited. Subscriptions only — no commissions, no data sales. About us →
Investing for the long term?
“Buy META when it closes above its 200-day average. Sell when it closes below.”
The 200-day average is its average closing price over the last 200 trading days.
In the 2021–22 crash, holding META fell 76.7%. This rule fell 22.1%.
- Holding META
- −76.7%
- This rule
- −22.1%
Drops this deep are where most people sell near the bottom. A rule makes that call for you, ahead of time.
Over 10 years it still made less than holding (+202.8% vs +376.8%). It gives up some of the gain to stay out of the worst drops.
Real daily prices · Oct 2016 – Nov 2026 · 0.1% costs a side · How we test
Start from a known portfolio.
- 60/40 mix60% US stocks, 40% bonds. Reset once a year.Worst drop−21.8%vs −21.8% just holding the same mixReturn +23.3% vs +27.9% holding itStart from this →
- PermanentFour equal parts: stocks, bonds, gold, cash.Worst drop−16.5%vs −16.5% just holding the same mixReturn +23.5% vs +35.2% holding itStart from this →
Oct 1, 2021 – Oct 1, 2026 · real prices