There are lots of services which provide stock market data on ticket-by-ticker basis, so to get the 1-min data for each US stock I will need to perform a few thousand requests each minute. Is there any service which provides something like a single CSV file updated every 1/5/15/60 mins with the data of all NYSE/NASDAQ stocks?
Algoseek is the source, interval aggregations available for bulk snapshots. Hope it helps.
Many Others can provide this as well, request a timely flat file snapshot. That kind of data can get pricey; not sure how much of a factor that is to you. Xignite is another source capable of generating such flat files for you.