Building a Stock Trading Journal for Kids
A practice ground for investing: real market prices, no real money lost, and a written 'why I bought it' required for every single order.
Whenever stocks come up in the news, to a child they're just numbers going up and down. More than investing itself, I wanted to give my kid one habit that investing forces on you: writing down 'why did I buy this?' in your own words. So I built a trading practice ground where no real money is at stake, but as much of the rest as possible is real.
Fake money, real prices
Each kid has their own account and trades against real Korean market prices — KOSPI and KOSDAQ. The prices have to be real for the waiting to be real. That urge to come back and check how the stock you bought did this week turns out to be more powerful than any educational content. Commissions and taxes are factored in like the real thing too. You have to feel your balance getting nibbled away by fees when you overtrade — that's part of what makes it true to life.
The heart isn't the chart — it's one written line
The heart of this app is a single text field on the order screen. Every buy and sell requires a reason before the order goes through. At first it's just a line like 'I think it'll go up.' But later, reading back their own records, the child discovers 'I bought it thinking it would go up, and it dropped' — by themselves. A parent saying that out loud and a kid facing it in their own handwriting are completely different things. There are daily profit-and-loss views, holdings, and stock detail screens with candles and moving averages, but they're all stage props for that one line.
Where it stands
The first set of features is finished and verified end to end locally — it's right before deployment. The plan is to run it inside the family first and sort out how to open it up after. Having built it, I've realized I could use it myself. An order where you can't write down why you're buying is an order an adult shouldn't be placing either.