Best way to measure inflation in real time? I'm looking to measure inflation in real time preferably minute to minute. What would be different feasible approaches to this? I know that the CPI measures inflation quite accurately but this is only on a month to month basis with the Bureau of Labour releasing their findings with a few month lag. The metric should be able to reflect a sudden inflationary spike like in the case of hyperinflation for example. Would much appreciate your help and thoughts!
The highest frequency real time data that I am aware of the Billion Prices Project, which is daily. Link to website. These are prices on the internet, which can be mapped to the US CPI relatively well.

Otherwise, consumer prices in bricks and mortar stores are Generally not set “minute by minute,” nor is there a way to sample them at that frequency. 

The closest you can get is countries in hyperinflation, where prices end up being indexed to a foreign currency. That is, the price paid is a fixed price in a foreign currency, multiplied by the exchange rate. This mechanism results in rapid changes, even during the time to drink a coffee (anecdote from the Weimar hyperinflation). Foreign exchange rates are the usual way of estimating a hyperinflation, since there is no good way to survey prices.