Consumer Price Index (CPI), explained.
How much the prices of a basket of everyday goods and services changed. 'Core' CPI strips out food and energy, which swing a lot.
Why it moves markets
Most central banks target inflation (often around 2%; the SARB targets 3–6%, with a stated preference for 4.5%). Inflation above or below expectations changes the odds of rate hikes or cuts, which moves the currency and bond yields.
Who publishes it, and when
National statistics agencies (BLS, ONS, Eurostat, Stats SA and others). Monthly in most economies; quarterly in Australia and New Zealand for the main release.
Pairs that often react
Pairs that include the currency involved usually react most. How much and in which direction depends on the surprise against expectations and on everything else going on. This isn't a prediction.
Educational only. Not advice and not a signal. Spreads often widen and prices can gap around big releases.