What is delta in order flow?

Delta is aggressive buy volume minus aggressive sell volume in a bar. Two hundred market buys and one hundred market sells is plus one hundred delta. That is arithmetic. It is not a forecast.

New order-flow traders see high positive delta and buy. That is the first trap. High buy delta can mean buyers already spent themselves into a resting sell wall. Price fails. The people who lifted the ask are now the trapped side. High negative delta into a bid that will not break is the same story flipped.

Use delta as effort. Use the next print as result. If effort and result disagree, that disagreement is the information. The number alone is not.

Sources: How to actually trade order flow