Grid trading, properly: what the mechanics actually are

Most people here treat grid bots as a crypto toy. They have been run on stocks and funds for far longer than that, and the mechanics are worth stating properly rather than dismissing, so here is the honest version. A grid divides a price range into levels. You buy one unit at each level going down, sell one unit at each level going up. That's it. You are not predicting direction — you are being paid for providing patience inside a range. Three parameters decide everything: the upper and lower boundary, the spacing between levels, and the size per level. Getting the boundary wrong is fatal, and I'll post about that separately. What it is good at: harvesting oscillation in a market that goes nowhere. What it is terrible at: a market that leaves the range and doesn't come back. Those are the same market on different days, which is the whole problem.