Just In Time Liquidity is an occurrence unique to Uniswap v3’s concentrated liquidity. A large amount of liquidity is added by a JIT bot when they see a large trade in the Ethereum mempool. It is then removed immediately after within the same block. The large amount of liquidity added before the trade reduces price impact for the trader by increasing the pool size, but at the same time dilutes the trading fees distributed amongst LPs from the trade. Unlike MEV, where a sandwiched trade causes a loss to the trader, JIT causes a loss to LPs.