data.cms.gov API

Quirks & gotchas

An unknown filter column is silently ignored: filter[Geo_Lvl] on a dataset whose column is Prscrbr_Geo_Lvl returns HTTP 200 and the unfiltered table, whose first rows are national totals — ask for one state, receive the nation. Filter values are matched case-insensitively. Every value is returned as a string, so FIPS codes must not be coerced or "01" becomes 1.0. A page caps at 6500 rows whatever size says; use offset. Row counts come from /data-viewer/stats, which accepts the same filters. Published rates are over Medicare denominators, not the general population.