diff --git a/NAMESPACE b/NAMESPACE
index bdf3211..d57090e 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -5,12 +5,8 @@ export(Data)
 export(DelayInterval)
 export(Exclusions)
 export(GenerationInterval)
-export(GpPrior)
 export(Parameters)
-export(Priors)
 export(RightTruncation)
-export(RtPrior)
-export(SamplerOpts)
 export(apply_exclusions)
 export(download_from_azure_blob)
 export(execute_model_logic)
diff --git a/NEWS.md b/NEWS.md
index eae644d..5907392 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,8 @@
 # CFAEpiNow2Pipeline (development version)
 
+* Creating a Config class to make syncing configuration differences easier.
+* Add a JSON reader for the Config class.
+* Use the Config class throughout the pipeline.
 * Adding a script to setup the Azure Batch Pool to link the container.
 * Adding new action to post a comment on PRs with a link to the rendered pkgdown site.
 * Add inner pipeline responsible for running the model fitting process
@@ -33,4 +36,3 @@
 * Fix bugs in parameter reading from local test run
 * Fix bugs in parameter reading from local test run
 * Add "US" as an option in `state_abb`
-* Creating a Config class to make syncing configuration differences easier.
diff --git a/R/config.R b/R/config.R
index 087849f..9cc8027 100644
--- a/R/config.R
+++ b/R/config.R
@@ -7,11 +7,14 @@ character_or_null <- S7::new_union(S7::class_character, NULL)
 #' @param path A string specifying the path to a CSV file containing exclusion
 #' data. It should include at least the columns: `reference_date`,
 #' `report_date`, ' `state_abb`, `disease`.
+#' @param blob_storage_container Optional. The name of the blob storage
+#' container to get it from. If NULL, will look locally.
 #' @export
 Exclusions <- S7::new_class(
   "Exclusions",
   properties = list(
-    path = character_or_null
+    path = character_or_null,
+    blob_storage_container = character_or_null
   )
 )
 
@@ -26,7 +29,7 @@ Exclusions <- S7::new_class(
 GenerationInterval <- S7::new_class(
   "GenerationInterval",
   properties = list(
-    path = S7::class_character,
+    path = character_or_null,
     blob_storage_container = character_or_null
   )
 )
@@ -42,7 +45,7 @@ GenerationInterval <- S7::new_class(
 DelayInterval <- S7::new_class(
   "DelayInterval",
   properties = list(
-    path = S7::class_character,
+    path = character_or_null,
     blob_storage_container = character_or_null
   )
 )
@@ -58,7 +61,7 @@ DelayInterval <- S7::new_class(
 RightTruncation <- S7::new_class(
   "RightTruncation",
   properties = list(
-    path = S7::class_character,
+    path = character_or_null,
     blob_storage_container = character_or_null
   )
 )
@@ -80,51 +83,6 @@ Parameters <- S7::new_class(
   )
 )
 
-#' RtPrior Class
-#'
-#' Represents the Rt prior parameters.
-#'
-#' @param mean A numeric value representing the mean of the Rt prior.
-#' @param sd A numeric value representing the standard deviation of the Rt
-#' prior.
-#' @export
-RtPrior <- S7::new_class(
-  "RtPrior",
-  properties = list(
-    mean = S7::class_numeric,
-    sd = S7::class_numeric
-  )
-)
-
-#' GpPrior Class
-#'
-#' Represents the Gaussian Process prior parameters.
-#'
-#' @param alpha_sd A numeric value representing the standard deviation of the
-#' alpha parameter in the GP prior.
-#' @export
-GpPrior <- S7::new_class(
-  "GpPrior",
-  properties = list(
-    alpha_sd = S7::class_numeric
-  )
-)
-
-#' Priors Class
-#'
-#' Holds all prior-related configurations for the pipeline.
-#'
-#' @param rt An instance of `RtPrior` class.
-#' @param gp An instance of `GpPrior` class.
-#' @export
-Priors <- S7::new_class(
-  "Priors",
-  properties = list(
-    rt = S7::S7_class(RtPrior()),
-    gp = S7::S7_class(GpPrior())
-  )
-)
-
 #' Data Class
 #'
 #' Represents the data-related configurations.
@@ -148,30 +106,6 @@ Data <- S7::new_class(
   )
 )
 
-#' SamplerOpts Class
-#'
-#' Represents the sampler options for the pipeline.
-#'
-#' @param cores An integer specifying the number of CPU cores to use.
-#' @param chains An integer specifying the number of Markov chains.
-#' @param iter_warmup An integer specifying the number of warmup iterations.
-#' @param iter_sampling An integer specifying the number of sampling iterations.
-#' @param adapt_delta A numeric value for the target acceptance probability.
-#' @param max_treedepth An integer specifying the maximum tree depth for the
-#' sampler.
-#' @export
-SamplerOpts <- S7::new_class(
-  "SamplerOpts",
-  properties = list(
-    cores = S7::class_integer,
-    chains = S7::class_integer,
-    iter_warmup = S7::class_integer,
-    iter_sampling = S7::class_integer,
-    adapt_delta = S7::class_numeric,
-    max_treedepth = S7::class_integer
-  )
-)
-
 #' Config Class
 #'
 #' Represents the complete configuration for the pipeline.
@@ -188,11 +122,13 @@ SamplerOpts <- S7::new_class(
 #' @param data An instance of `Data` class containing data configurations.
 #' @param seed An integer for setting the random seed.
 #' @param horizon An integer specifying the forecasting horizon.
-#' @param priors An instance of `Priors` class containing prior configurations.
+#' @param priors A list of lists. The first level should contain the key `rt`
+#' with elements `mean` and `sd` and the key `gp` with element `alpha_sd`.
 #' @param parameters An instance of `Parameters` class containing parameter
 #' configurations.
-#' @param sampler_opts An instance of `SamplerOpts` class containing sampler
-#' options.
+#' @param sampler_opts A list. The Stan sampler options to be passed through
+#' EpiNow2. It has required keys: `cores`, `chains`, `iter_warmup`,
+#' `iter_sampling`, `max_treedepth`, and `adapt_delta`.
 #' @param exclusions An instance of `Exclusions` class containing exclusion
 #' criteria.
 #' @param config_version A numeric value specifying the configuration version.
@@ -201,6 +137,8 @@ SamplerOpts <- S7::new_class(
 #' @param model A string specifying the model to be used.
 #' @param report_date A string representing the report date. Formatted as
 #' "YYYY-MM-DD".
+#' @param as_of_date A string representing the as-of date. Formatted as
+#' "YYYY-MM-DD".
 #' @export
 Config <- S7::new_class(
   "Config",
@@ -210,6 +148,7 @@ Config <- S7::new_class(
     min_reference_date = S7::class_character,
     max_reference_date = S7::class_character,
     report_date = S7::class_character,
+    as_of_date = S7::class_character,
     disease = S7::class_character,
     geo_value = S7::class_character,
     geo_type = S7::class_character,
@@ -219,9 +158,30 @@ Config <- S7::new_class(
     config_version = S7::class_character,
     quantile_width = S7::new_property(S7::class_vector, default = c(0.5, 0.95)),
     data = S7::S7_class(Data()),
-    priors = S7::S7_class(Priors()),
+    # Using a list instead of an S7 object, because EpiNow2 expects a list, and
+    # because it reduces changes to the pipeline code.
+    # Adding a default that shows the required keys, with the expected types as
+    # the values. Should fail loudly if the default values are used, but will
+    # be useful to the user to see what is expected.
+    priors = S7::new_property(S7::class_list, default = list(
+      rt = list(mean = S7::class_numeric, sd = S7::class_numeric),
+      gp = list(alpha_sd = S7::class_numeric)
+    )),
     parameters = S7::S7_class(Parameters()),
-    sampler_opts = S7::S7_class(SamplerOpts()),
+    # Using a list instead of an S7 object, because stan expects a list, and
+    # because it reduces changes to the pipeline code.
+    # Adding a default that shows the required keys, with the expected types as
+    # the values. Should fail loudly if the default values are used, but will
+    # be useful to the user to see what is expected.
+    # Using a list here also reduces changes to the pipeline code.
+    sampler_opts = S7::new_property(S7::class_list, default = list(
+      cores = S7::class_integer,
+      chains = S7::class_integer,
+      iter_warmup = S7::class_integer,
+      iter_sampling = S7::class_integer,
+      max_treedepth = S7::class_integer,
+      adapt_delta = S7::class_numeric
+    )),
     exclusions = S7::S7_class(Exclusions())
   )
 )
@@ -242,12 +202,8 @@ read_json_into_config <- function(config_path) {
   # create a more automated way to do this, we can remove this.
   str2class <- list(
     data = Data,
-    priors = Priors,
     parameters = Parameters,
-    sampler_opts = SamplerOpts,
     exclusions = Exclusions,
-    rt = RtPrior,
-    gp = GpPrior,
     generation_interval = GenerationInterval,
     delay_interval = DelayInterval,
     right_truncation = RightTruncation
@@ -260,9 +216,9 @@ read_json_into_config <- function(config_path) {
   missing_properties <- setdiff(S7::prop_names(Config()), names(raw_input))
   # Error out if missing any fields
   if (length(missing_properties) > 0) {
-    cli::cli_abort(c(
-      "The following properties are missing from the config file:",
-      "{.var missing_properties}"
+    cli::cli_alert_info(c(
+      "The following expected properties were not in the config file:",
+      "{.var {missing_properties}}"
     ))
   }
 
@@ -279,7 +235,9 @@ read_json_into_config <- function(config_path) {
           raw_data[[prop_name]], str2class[[prop_name]]
         )
       } else if (!(prop_name %in% S7::prop_names(class_to_fill()))) {
-        cli::cli_warn("No Config field matching {.var {prop_name}}. Not using.")
+        cli::cli_alert_info(
+          "No Config field matching {.var {prop_name}}. Not using."
+        )
       } else {
         # Else set it directly
         S7::prop(config, prop_name) <- raw_data[[prop_name]]
diff --git a/R/pipeline.R b/R/pipeline.R
index a51a169..7ed7bc7 100644
--- a/R/pipeline.R
+++ b/R/pipeline.R
@@ -71,15 +71,24 @@
 orchestrate_pipeline <- function(config_path,
                                  blob_storage_container = NULL,
                                  output_dir = "/") {
-  # TODO: Add config reader here
-  config <- jsonlite::read_json(config_path,
-    simplifyVector = TRUE
+  config <- rlang::try_fetch(
+    read_json_into_config(config_path),
+    error = function(con) {
+      cli::cli_warn("Bad config file",
+        parent = con,
+        class = "Bad_config"
+      )
+      FALSE
+    }
   )
+  if (typeof(config) == "logical") {
+    return(invisible(FALSE))
+  }
 
   write_output_dir_structure(
     output_dir = output_dir,
-    job_id = config[["job_id"]],
-    task_id = config[["task_id"]]
+    job_id = config@job_id,
+    task_id = config@task_id
   )
 
   # Set up logs
@@ -104,8 +113,8 @@ orchestrate_pipeline <- function(config_path,
   )
   on.exit(sink(file = NULL))
   cli::cli_alert_info("Starting run at {Sys.time()}")
-  cli::cli_alert_info("Using job id {.field {config[['job_id']]}}")
-  cli::cli_alert_info("Using task id {.field {config[['task_id']]}}")
+  cli::cli_alert_info("Using job id {.field {config@job_id}}")
+  cli::cli_alert_info("Using task id {.field {config@task_id}}")
 
   # Errors within `execute_model_logic()` are downgraded to warnings so
   # they can be logged and stored in Blob. If there is an error,
@@ -153,7 +162,8 @@ execute_model_logic <- function(config, output_dir) {
     min_reference_date = config@min_reference_date
   )
 
-  if (!rlang::is_null(config@exclusions@path)) {
+  # rlang::is_empty() checks for empty and NULL values
+  if (!rlang::is_empty(config@exclusions@path)) {
     exclusions_df <- read_exclusions(config@exclusions@path)
     cases_df <- apply_exclusions(cases_df, exclusions_df)
   } else {
diff --git a/man/Config.Rd b/man/Config.Rd
index 7f75f9c..7ab564b 100644
--- a/man/Config.Rd
+++ b/man/Config.Rd
@@ -10,6 +10,7 @@ Config(
   min_reference_date = character(0),
   max_reference_date = character(0),
   report_date = character(0),
+  as_of_date = character(0),
   disease = character(0),
   geo_value = character(0),
   geo_type = character(0),
@@ -19,9 +20,142 @@ Config(
   config_version = character(0),
   quantile_width = c(0.5, 0.95),
   data = Data(),
-  priors = Priors(),
+  priors = list(rt = list(mean = structure(list(classes = list(structure(list(class =
+    "integer", constructor_name = "integer", constructor = function (.data = integer(0))
+    
+ .data, validator = function (object) 
+ {
+     if (base_class(object) != name) {
+   
+         sprintf("Underlying data must be <\%s> not <\%s>", name, base_class(object))
+   
+     }
+ }), class = "S7_base_class"), structure(list(class = "double", constructor_name =
+    "double", constructor = function (.data = numeric(0)) 
+ .data, validator = function
+    (object) 
+ {
+     if (base_class(object) != name) {
+        
+    sprintf("Underlying data must be <\%s> not <\%s>", name, base_class(object))
+     }
+
+    }), class = "S7_base_class"))), class = "S7_union"), sd = structure(list(classes =
+    list(structure(list(class = "integer", constructor_name = "integer", constructor =
+    function (.data = integer(0)) 
+ .data, validator = function (object) 
+ {
+     if
+    (base_class(object) != name) {
+        
+    sprintf("Underlying data must be <\%s> not <\%s>", name, base_class(object))
+     }
+
+    }), class = "S7_base_class"), structure(list(class = "double", constructor_name =
+    "double", constructor = function (.data = numeric(0)) 
+ .data, validator = function
+    (object) 
+ {
+     if (base_class(object) != name) {
+        
+    sprintf("Underlying data must be <\%s> not <\%s>", name, base_class(object))
+     }
+
+    }), class = "S7_base_class"))), class = "S7_union")), gp = list(alpha_sd =
+    structure(list(classes = list(structure(list(class = "integer", constructor_name =
+    "integer", constructor = function (.data = integer(0)) 
+ .data, validator = function
+    (object) 
+ {
+     if (base_class(object) != name) {
+        
+    sprintf("Underlying data must be <\%s> not <\%s>", name, base_class(object))
+     }
+
+    }), class = "S7_base_class"), structure(list(class = "double", constructor_name =
+    "double", constructor = function (.data = numeric(0)) 
+ .data, validator = function
+    (object) 
+ {
+     if (base_class(object) != name) {
+        
+    sprintf("Underlying data must be <\%s> not <\%s>", name, base_class(object))
+     }
+
+    }), class = "S7_base_class"))), class = "S7_union"))),
   parameters = Parameters(),
-  sampler_opts = SamplerOpts(),
+  sampler_opts = list(cores = structure(list(class = "integer", constructor_name =
+    "integer", constructor = function (.data = integer(0)) 
+ .data, validator = function
+    (object) 
+ {
+     if (base_class(object) != name) {
+        
+    sprintf("Underlying data must be <\%s> not <\%s>", name, base_class(object))
+     }
+
+    }), class = "S7_base_class"), chains = structure(list(class = "integer",
+    constructor_name = "integer", constructor = function (.data = integer(0)) 
+ .data,
+    validator = function (object) 
+ {
+     if (base_class(object) != name) {
+        
+    sprintf("Underlying data must be <\%s> not <\%s>", name, base_class(object))
+     }
+
+    }), class = "S7_base_class"), iter_warmup = structure(list(class = "integer",
+    constructor_name = "integer", constructor = function (.data = integer(0)) 
+ .data,
+    validator = function (object) 
+ {
+     if (base_class(object) != name) {
+        
+    sprintf("Underlying data must be <\%s> not <\%s>", name, base_class(object))
+     }
+
+    }), class = "S7_base_class"), iter_sampling = structure(list(class = "integer",
+    constructor_name = "integer", constructor = function (.data = integer(0)) 
+ .data,
+    validator = function (object) 
+ {
+     if (base_class(object) != name) {
+        
+    sprintf("Underlying data must be <\%s> not <\%s>", name, base_class(object))
+     }
+
+    }), class = "S7_base_class"), max_treedepth = structure(list(class = "integer",
+    constructor_name = "integer", constructor = function (.data = integer(0)) 
+ .data,
+    validator = function (object) 
+ {
+     if (base_class(object) != name) {
+        
+    sprintf("Underlying data must be <\%s> not <\%s>", name, base_class(object))
+     }
+
+    }), class = "S7_base_class"), adapt_delta = structure(list(classes =
+    list(structure(list(class = "integer", constructor_name = "integer", constructor =
+    function (.data = integer(0)) 
+ .data, validator = function (object) 
+ {
+     if
+    (base_class(object) != name) {
+        
+    sprintf("Underlying data must be <\%s> not <\%s>", name, base_class(object))
+     }
+
+    }), class = "S7_base_class"), structure(list(class = "double", constructor_name =
+    "double", constructor = function (.data = numeric(0)) 
+ .data, validator = function
+    (object) 
+ {
+     if (base_class(object) != name) {
+        
+    sprintf("Underlying data must be <\%s> not <\%s>", name, base_class(object))
+     }
+
+    }), class = "S7_base_class"))), class = "S7_union")),
   exclusions = Exclusions()
 )
 }
@@ -39,6 +173,9 @@ date. Formatted as "YYYY-MM-DD".}
 \item{report_date}{A string representing the report date. Formatted as
 "YYYY-MM-DD".}
 
+\item{as_of_date}{A string representing the as-of date. Formatted as
+"YYYY-MM-DD".}
+
 \item{disease}{A string specifying the disease being modeled.}
 
 \item{geo_value}{A string specifying the geographic value, usually a state.}
@@ -58,13 +195,15 @@ quantiles.}
 
 \item{data}{An instance of \code{Data} class containing data configurations.}
 
-\item{priors}{An instance of \code{Priors} class containing prior configurations.}
+\item{priors}{A list of lists. The first level should contain the key \code{rt}
+with elements \code{mean} and \code{sd} and the key \code{gp} with element \code{alpha_sd}.}
 
 \item{parameters}{An instance of \code{Parameters} class containing parameter
 configurations.}
 
-\item{sampler_opts}{An instance of \code{SamplerOpts} class containing sampler
-options.}
+\item{sampler_opts}{A list. The Stan sampler options to be passed through
+EpiNow2. It has required keys: \code{cores}, \code{chains}, \code{iter_warmup},
+\code{iter_sampling}, \code{max_treedepth}, and \code{adapt_delta}.}
 
 \item{exclusions}{An instance of \code{Exclusions} class containing exclusion
 criteria.}
diff --git a/man/Exclusions.Rd b/man/Exclusions.Rd
index 9f4c43a..d58cc13 100644
--- a/man/Exclusions.Rd
+++ b/man/Exclusions.Rd
@@ -4,12 +4,15 @@
 \alias{Exclusions}
 \title{Exclusions Class}
 \usage{
-Exclusions(path = character(0))
+Exclusions(path = character(0), blob_storage_container = character(0))
 }
 \arguments{
 \item{path}{A string specifying the path to a CSV file containing exclusion
 data. It should include at least the columns: \code{reference_date},
 \code{report_date}, ' \code{state_abb}, \code{disease}.}
+
+\item{blob_storage_container}{Optional. The name of the blob storage
+container to get it from. If NULL, will look locally.}
 }
 \description{
 Represents exclusion criteria for the pipeline.
diff --git a/man/GpPrior.Rd b/man/GpPrior.Rd
deleted file mode 100644
index ea5ec25..0000000
--- a/man/GpPrior.Rd
+++ /dev/null
@@ -1,15 +0,0 @@
-% Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/config.R
-\name{GpPrior}
-\alias{GpPrior}
-\title{GpPrior Class}
-\usage{
-GpPrior(alpha_sd = integer(0))
-}
-\arguments{
-\item{alpha_sd}{A numeric value representing the standard deviation of the
-alpha parameter in the GP prior.}
-}
-\description{
-Represents the Gaussian Process prior parameters.
-}
diff --git a/man/Priors.Rd b/man/Priors.Rd
deleted file mode 100644
index 8845c92..0000000
--- a/man/Priors.Rd
+++ /dev/null
@@ -1,16 +0,0 @@
-% Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/config.R
-\name{Priors}
-\alias{Priors}
-\title{Priors Class}
-\usage{
-Priors(rt = RtPrior(), gp = GpPrior())
-}
-\arguments{
-\item{rt}{An instance of \code{RtPrior} class.}
-
-\item{gp}{An instance of \code{GpPrior} class.}
-}
-\description{
-Holds all prior-related configurations for the pipeline.
-}
diff --git a/man/RtPrior.Rd b/man/RtPrior.Rd
deleted file mode 100644
index 2b99938..0000000
--- a/man/RtPrior.Rd
+++ /dev/null
@@ -1,17 +0,0 @@
-% Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/config.R
-\name{RtPrior}
-\alias{RtPrior}
-\title{RtPrior Class}
-\usage{
-RtPrior(mean = integer(0), sd = integer(0))
-}
-\arguments{
-\item{mean}{A numeric value representing the mean of the Rt prior.}
-
-\item{sd}{A numeric value representing the standard deviation of the Rt
-prior.}
-}
-\description{
-Represents the Rt prior parameters.
-}
diff --git a/man/SamplerOpts.Rd b/man/SamplerOpts.Rd
deleted file mode 100644
index f3149da..0000000
--- a/man/SamplerOpts.Rd
+++ /dev/null
@@ -1,32 +0,0 @@
-% Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/config.R
-\name{SamplerOpts}
-\alias{SamplerOpts}
-\title{SamplerOpts Class}
-\usage{
-SamplerOpts(
-  cores = integer(0),
-  chains = integer(0),
-  iter_warmup = integer(0),
-  iter_sampling = integer(0),
-  adapt_delta = integer(0),
-  max_treedepth = integer(0)
-)
-}
-\arguments{
-\item{cores}{An integer specifying the number of CPU cores to use.}
-
-\item{chains}{An integer specifying the number of Markov chains.}
-
-\item{iter_warmup}{An integer specifying the number of warmup iterations.}
-
-\item{iter_sampling}{An integer specifying the number of sampling iterations.}
-
-\item{adapt_delta}{A numeric value for the target acceptance probability.}
-
-\item{max_treedepth}{An integer specifying the maximum tree depth for the
-sampler.}
-}
-\description{
-Represents the sampler options for the pipeline.
-}
diff --git a/tests/testthat/test-pipeline.R b/tests/testthat/test-pipeline.R
index 08bad59..a0dda93 100644
--- a/tests/testthat/test-pipeline.R
+++ b/tests/testthat/test-pipeline.R
@@ -71,7 +71,7 @@ test_that("Pipeline run produces expected outputs with exclusions", {
 test_that("Process pipeline produces expected outputs and returns success", {
   # Arrange
   config_path <- test_path("data", "sample_config_with_exclusion.json")
-  config <- jsonlite::read_json(config_path)
+  config <- read_json_into_config(config_path)
   # Read from locally
   output_dir <- "pipeline_test"
   on.exit(unlink(output_dir, recursive = TRUE))
@@ -87,7 +87,7 @@ test_that("Process pipeline produces expected outputs and returns success", {
   # Assert output files all exist
   expect_pipeline_files_written(
     output_dir,
-    config[["job_id"]],
-    config[["task_id"]]
+    config@job_id,
+    config@task_id
   )
 })