Explore real markets back to 2015, build an idea of your own, and watch every trade it would have made. Then let it run on live prices with pretend money, while you follow along from your phone.
Three steps, and the first takes less than a minute.
Every market is a living line of its real price. Travel back through years of it, zoom into a day, see what moved.
Snap pieces together, say it in a short sentence, or write it as code. Every trade it would have made appears, and you can ask why it made each one.
Start it on live prices with pretend money and it keeps trading around the clock. Your phone tells you each time it does.
Genesis is built so a test can't flatter an idea.
A test only ever knows what was known at each moment. Peeking ahead isn't a mistake you have to avoid; it's impossible.
Every result says which prices it used, what trading cost, and what it left out. Trying many settings until one looks good is counted against the result.
Change any part of an idea in words and see the difference at once. Keep versions, compare them, and build up a world of your own.