Tick Size – The minimum price increment by which a currency pair can move. In Forex, this usually corresponds to one pip (often 0.0001 for most pairs, or 0.01 for JPY pairs). For example, EUR/USD changing from 1.1700 to 1.1701 is one tick/pip. Tick size is defined by the market or broker and determines price granularity. Knowing the tick size helps a robot calculate price steps and risk. Platforms typically provide symbol.TickSize
or similar. Tick size can affect slippage and spread resolution.