cast_api_queries: cast-API snapshot and archive queries

In epidatr: Client for Delphi's 'Epidata' API

cast-API snapshot and archive queries

Description

• epidata_snapshot fetches a snapshot of signals as they appeared at a specific date (or the latest available if snapshot_date is omitted).

• epidata_archive fetches the full version history of signals across all available issues.

• epidata is a wrapper that routes to one of the above based on which versioning argument is supplied.

Usage

epidata_snapshot(
  source,
  signals,
  geo_type,
  geo_values = "*",
  reference_time = "*",
  time_values = lifecycle::deprecated(),
  ...,
  fill_method = NULL,
  snapshot_date = NULL,
  as_of = lifecycle::deprecated(),
  fetch_args = fetch_args_list()
)

epidata_archive(
  source,
  signals,
  geo_type,
  geo_values = "*",
  reference_time = "*",
  time_values = lifecycle::deprecated(),
  ...,
  fill_method = NULL,
  report_time = "*",
  issues = lifecycle::deprecated(),
  fetch_args = fetch_args_list()
)

epidata(
  source,
  signals,
  geo_type,
  geo_values = "*",
  reference_time = "*",
  time_values = lifecycle::deprecated(),
  ...,
  fill_method = NULL,
  snapshot_date = NULL,
  as_of = lifecycle::deprecated(),
  report_time = NULL,
  issues = lifecycle::deprecated(),
  fetch_args = fetch_args_list()
)

Arguments

source	string. The data source to query (e.g., "nssp", "nhsn"). Use epidata_meta() to discover available sources.
signals	character vector. One or more signals to query for the given source. Use epidata_meta() to discover available signals.
geo_type	string. The geography type to query (e.g., "state", "nation", "county"). Use epidata_meta() to discover available geo types for a given source and signal.
geo_values	character. The geographies to return. Defaults to all ("*") geographies within requested geographic resolution (see: https://cmu-delphi.github.io/delphi-epidata/api/covidcast_geography.html.).
reference_time	timeset. Reference time to return (filters on the reference_time column). Supports individual dates or epirange(). Defaults to all ("*"). Filtered locally after the API call.
time_values	Use reference_time instead.
...	not used for values, forces later arguments to bind by name
fill_method	string. Optional filter to an imputation method. The API provides alternatives of the same signal differing in how nulls were handled during geographic aggregation: "source" means no imputation or aggregation (raw source data), "fill_ave" fills nulls with the average of neighboring values, and "fill_zero" fills nulls with zero. NULL (default) returns all fill methods.
snapshot_date	Date or NULL. The snapshot date; NULL returns the latest available version.
as_of	Use snapshot_date instead.
fetch_args	fetch_args_list(). Additional arguments to pass to fetch(). See fetch_args_list() for details.
report_time	Date, string, or epirange(). A query on the report_time column for the archive endpoint. Supports exact dates (e.g., "2025-10-16"), operators (e.g., "<2025-10-16"), or an epirange(). Internally maps to the version_query API parameter.
issues	Use report_time instead.

Value

tibble::tibble

Data Versioning

epidata supports two mutually exclusive versioning arguments. Pass snapshot_date to retrieve data as it appeared on a specific date, or report_time to query the archive by when data was reported. If neither is supplied, epidata returns the latest available snapshot.

See also

For example queries showing how to discover signals and build calls, see vignette("signal-discovery", package = "epidatr").

See Also

epidata_meta(), epirange()

epidatr documentation built on June 3, 2026, 1:06 a.m.