diff --git a/R/GlobalSetter.R b/R/GlobalSetter.R
new file mode 100644
index 0000000000..b3ef4e2bb0
--- /dev/null
+++ b/R/GlobalSetter.R
@@ -0,0 +1,94 @@
+#' Set global objects
+#'
+#' Class to manage global objects and bring them into scope of `shiny` modules.
+#'
+#' Singleton object to pass variables between modules. Instantiated in the package namespace.
+#' Global objects are stored in the `session$userData` environment.
+#' Every `shiny` module can register a setter functions for a global variable to be taken from storage
+#' or created from scratch. Then, that function can be called anywhere in the app.
+#'
+#' @docType class
+#' @name GlobalSetter
+#' @rdname GlobalSetter
+#'
+#' @examples
+#' GlobalSetter <- getFromNamespace("GlobalSetter", "teal")
+#' setter <- GlobalSetter$new()
+#' setter$add_setter("romans", function() {
+#'   assign("romans", .romans, envir = .GlobalEnv)
+#'   .romans
+#'   })
+#' setter
+#' setter$set_global("romans")
+#' exists("romans", envir = .GlobalEnv, inherits = TRUE)
+#'
+#' @keywords internal
+#'
+GlobalSetter <- R6::R6Class(
+  classname = "GlobalSetter",
+
+  # __Public Methods ----
+  public = list(
+
+    #' @description
+    #' Set object.
+    #' @param obj (`character(1)`) Name of object to set.
+    #' @return
+    #' Whatever the particular setter function returns, usually the global object.
+    set_global = function(obj) {
+      if (!shiny::isRunning()) {
+        message("no shiny, no objects")
+        return(NULL)
+      }
+      checkmate::assert_string(obj)
+      checkmate::assert_choice(obj, private$objects)
+
+      ind <- match(obj, private$objects)
+      private$functions[[ind]]()
+    },
+
+    #' @description
+    #' Add setter function for global object.
+    #' @param obj (`character(1)`) Name of object.
+    #' @param fun (`function`) Setter function.
+    add_setter = function(obj, fun) {
+      checkmate::assert_string(obj)
+      checkmate::assert_function(fun)
+
+      ind <- match(obj, private$objects, nomatch = length(private$objects) + 1L)
+
+      if (is.element(obj, private$objects)) {
+        if (identical(fun, private$functions[[ind]])) {
+          message("this setter already exists")
+          return(invisible(NULL))
+        } else {
+          message(sprintf("overwriting setter function for object '%s'", obj))
+        }
+      }
+
+      private$objects[ind] <- obj
+      private$functions[[ind]] <- fun
+      invisible(NULL)
+    },
+
+    #' @noRd
+    format = function(...) {
+      paste(
+        c(
+          "Global Object Setter",
+          if (length(private$objects)) sprintf("  objects: %s", toString(private$objects)) else "  empty"
+        ),
+        collapse = "\n"
+      )
+    }
+  ),
+
+  # __Private Members ----
+  private = list(
+    objects = character(0L), # objects for which setter functions have been defined
+    functions = list() # setter functions
+  ),
+  cloneable = FALSE
+)
+
+GS <- GlobalSetter$new()
diff --git a/R/module_filter_manager.R b/R/module_filter_manager.R
index fb735a2366..95e65e7589 100644
--- a/R/module_filter_manager.R
+++ b/R/module_filter_manager.R
@@ -113,43 +113,22 @@ filter_manager_srv <- function(id, filtered_data_list, filter) {
 
     is_module_specific <- isTRUE(attr(filter, "module_specific"))
 
+    # Register setters for global objects
+    GS$add_setter("slices_global", setter_slices_global)
+    GS$add_setter("filtered_data_list", setter_filtered_data_list)
+    GS$add_setter("mapping_matrix", setter_mapping_matrix)
+
     # Create global list of slices.
     # Contains all available teal_slice objects available to all modules.
     # Passed whole to instances of FilteredData used for individual modules.
     # Down there a subset that pertains to the data sets used in that module is applied and displayed.
-    slices_global <- reactiveVal(filter)
-
-    filtered_data_list <-
-      if (!is_module_specific) {
-        # Retrieve the first FilteredData from potentially nested list.
-        # List of length one is named "global_filters" because that name is forbidden for a module label.
-        list(global_filters = unlist(filtered_data_list)[[1]])
-      } else {
-        # Flatten potentially nested list of FilteredData objects while maintaining useful names.
-        # Simply using `unlist` would result in concatenated names.
-        flatten_nested <- function(x, name = NULL) {
-          if (inherits(x, "FilteredData")) {
-            setNames(list(x), name)
-          } else {
-            unlist(lapply(names(x), function(name) flatten_nested(x[[name]], name)))
-          }
-        }
-        flatten_nested(filtered_data_list)
-      }
-
-    # Create mapping fo filters to modules in matrix form (presented as data.frame).
-    # Modules get NAs for filters that cannot be set for them.
-    mapping_matrix <- reactive({
-      state_ids_global <- vapply(slices_global(), `[[`, character(1L), "id")
-      mapping_smooth <- lapply(filtered_data_list, function(x) {
-        state_ids_local <- vapply(x$get_filter_state(), `[[`, character(1L), "id")
-        state_ids_allowed <- vapply(x$get_available_teal_slices()(), `[[`, character(1L), "id")
-        states_active <- state_ids_global %in% state_ids_local
-        ifelse(state_ids_global %in% state_ids_allowed, states_active, NA)
-      })
-
-      as.data.frame(mapping_smooth, row.names = state_ids_global, check.names = FALSE)
-    })
+    slices_global <- GS$set_global("slices_global")
+    # Prepare FilteredData object according to app type (global/module-specific).
+    filtered_data_list <- GS$set_global("filtered_data_list")
+    # Represent mapping of modules to filters.
+    mapping_matrix <- GS$set_global("mapping_matrix")
+    # The three objects above are also stored in the app session's userData.
+    # They will be used in other modules and stored when bookmarking.
 
     output$slices_table <- renderTable(
       expr = {
@@ -182,9 +161,9 @@ filter_manager_srv <- function(id, filtered_data_list, filter) {
     })
 
     # Call snapshot manager.
-    snapshot_history <- snapshot_manager_srv("snapshot_manager", slices_global, mapping_matrix, filtered_data_list)
+    snapshot_manager_srv("snapshot_manager")
     # Call state manager.
-    state_manager_srv("state_manager", slices_global, mapping_matrix, filtered_data_list, snapshot_history)
+    state_manager_srv("state_manager")
 
     modules_out # returned for testing purpose
   })
@@ -252,3 +231,96 @@ filter_manager_module_srv <- function(id, module_fd, slices_global) {
     slices_module # returned for testing purpose
   })
 }
+
+
+
+# utility functions ----
+
+# Functions that prepare objects.
+# Objects are first scoped in sesion (userData) and if not found, created and stored.
+
+# Obtain appropriate structure of `FilteredData` objects.
+# For global app, list of length 1 named "global_filters".
+# For module-specific app, list of length one-per-module, named after modules.
+#' @keywords internal
+#' @noRd
+#'
+create_filtered_data_list <- function(filtered_data_list, module_specific) {
+  if (!module_specific) {
+    # Retrieve the first FilteredData from potentially nested list.
+    # List of length one is named "global_filters" because that name is forbidden for a module label.
+    list(global_filters = unlist(filtered_data_list)[[1]])
+  } else {
+    flatten_nested(filtered_data_list)
+  }
+}
+# Flatten potentially nested list of FilteredData objects while maintaining useful names.
+# Simply using `unlist` would result in concatenated names.
+#' @keywords internal
+#' @noRd
+#'
+flatten_nested <- function(x, name = NULL) {
+  if (inherits(x, "FilteredData")) {
+    setNames(list(x), name)
+  } else {
+    unlist(lapply(names(x), function(name) flatten_nested(x[[name]], name)))
+  }
+}
+
+# Create mapping fo filters to modules in matrix form (presented as data.frame).
+# Modules get NAs for filters that cannot be set for them.
+#' @keywords internal
+#' @noRd
+#'
+create_mapping_matrix <- function(filtered_data_list, slices_global) {
+  reactive({
+    state_ids_global <- vapply(slices_global(), `[[`, character(1L), "id")
+    mapping_smooth <- lapply(filtered_data_list, function(x) {
+      state_ids_local <- vapply(x$get_filter_state(), `[[`, character(1L), "id")
+      state_ids_allowed <- vapply(x$get_available_teal_slices()(), `[[`, character(1L), "id")
+      states_active <- state_ids_global %in% state_ids_local
+      ifelse(state_ids_global %in% state_ids_allowed, states_active, NA)
+    })
+
+    as.data.frame(mapping_smooth, row.names = state_ids_global, check.names = FALSE)
+  })
+}
+
+
+
+# setter for global variable ----
+#' @keywords internal
+#' @noRd
+setter_slices_global <- function() {
+  sesh <- getDefaultReactiveDomain()
+  if (is.null(sesh$userData$slices_global)) {
+    filter <- dynGet("filter")
+    sesh$userData$slices_global <- reactiveVal(filter)
+  } else {
+    sesh$userData$slices_global
+  }
+}
+#' @keywords internal
+#' @noRd
+setter_filtered_data_list <- function() {
+  sesh <- getDefaultReactiveDomain()
+  if (is.null(sesh$userData$filtered_data_list)) {
+    filtered_data_list <- dynGet("filtered_data_list")
+    is_module_specific <- dynGet("is_module_specific")
+    sesh$userData$filtered_data_list <- create_filtered_data_list(filtered_data_list, is_module_specific)
+  } else {
+    sesh$userData$filtered_data_list
+  }
+}
+#' @keywords internal
+#' @noRd
+setter_mapping_matrix <- function() {
+  sesh <- getDefaultReactiveDomain()
+  if (is.null(sesh$userData$mapping_matrix)) {
+    filtered_data_list <- dynGet("filtered_data_list")
+    slices_global <- dynGet("slices_global")
+    sesh$userData$mapping_matrix <- create_mapping_matrix(filtered_data_list, slices_global)
+  } else {
+    sesh$userData$mapping_matrix
+  }
+}
diff --git a/R/module_snapshot_manager.R b/R/module_snapshot_manager.R
index 5f47c8597f..0a3e1abaa9 100644
--- a/R/module_snapshot_manager.R
+++ b/R/module_snapshot_manager.R
@@ -102,24 +102,21 @@ snapshot_manager_ui <- function(id) {
 #' @rdname snapshot_manager_module
 #' @keywords internal
 #'
-snapshot_manager_srv <- function(id, slices_global, mapping_matrix, filtered_data_list) {
+snapshot_manager_srv <- function(id) {
   checkmate::assert_character(id)
-  checkmate::assert_true(is.reactive(slices_global))
-  checkmate::assert_class(isolate(slices_global()), "teal_slices")
-  checkmate::assert_true(is.reactive(mapping_matrix))
-  checkmate::assert_data_frame(isolate(mapping_matrix()), null.ok = TRUE)
-  checkmate::assert_list(filtered_data_list, types = "FilteredData", any.missing = FALSE, names = "named")
 
   moduleServer(id, function(input, output, session) {
     ns <- session$ns
 
+    # Retrieve global objects ----
+    slices_global <- GS$set_global("slices_global")
+    filtered_data_list <- GS$set_global("filtered_data_list")
+    mapping_matrix <- GS$set_global("mapping_matrix")
+
+    # Register setter for global snapshot history ----
+    GS$add_setter("snapshot_history", setter_snapshot_history)
     # Store global filter states ----
-    filter <- isolate(slices_global())
-    snapshot_history <- reactiveVal({
-      list(
-        "Initial application state" = as.list(filter, recursive = TRUE)
-      )
-    })
+    snapshot_history <- GS$set_global("snapshot_history")
 
     # Snapshot current application state ----
     # Name snaphsot.
@@ -326,14 +323,13 @@ snapshot_manager_srv <- function(id, slices_global, mapping_matrix, filtered_dat
       }
     })
 
-    return(snapshot_history)
   })
 }
 
 
 
 
-### utility functions ----
+# utility functions ----
 
 #' Explicitly enumerate global filters.
 #'
@@ -343,6 +339,7 @@ snapshot_manager_srv <- function(id, slices_global, mapping_matrix, filtered_dat
 #' @param module_names (`character`) vector containing names of all modules in the app
 #' @return A `named_list` with one element per module, each element containing all filters applied to that module.
 #' @keywords internal
+#' @noRd
 #'
 unfold_mapping <- function(mapping, module_names) {
   module_names <- structure(module_names, names = module_names)
@@ -360,6 +357,7 @@ unfold_mapping <- function(mapping, module_names) {
 #'                       columns represent modules and row represent `teal_slice`s
 #' @return `named list` like that in the `mapping` attribute of a `teal_slices` object.
 #' @keywords internal
+#' @noRd
 #'
 matrix_to_mapping <- function(mapping_matrix) {
   mapping_matrix[] <- lapply(mapping_matrix, function(x) x | is.na(x))
@@ -370,3 +368,22 @@ matrix_to_mapping <- function(mapping_matrix) {
   mapping <- c(lapply(local_filters, function(x) rownames(local_filters)[x]), list(global_filters = global_filters))
   Filter(function(x) length(x) != 0L, mapping)
 }
+
+
+
+# setter for global variable ----
+#' @keywords internal
+#' @noRd
+setter_snapshot_history <- function() {
+  sesh <- getDefaultReactiveDomain()
+  if (is.null(sesh$userData$snapshot_history)) {
+    slices_global <- dynGet("slices_global")
+    sesh$userData$snapshot_history <- reactiveVal({
+      list(
+        "Initial application state" = as.list(isolate(slices_global()), recursive = TRUE)
+      )
+    })
+  } else {
+    sesh$userData$snapshot_history
+  }
+}
diff --git a/R/module_state_manager.R b/R/module_state_manager.R
index 76a59dd477..38e9c67886 100644
--- a/R/module_state_manager.R
+++ b/R/module_state_manager.R
@@ -33,24 +33,24 @@ state_manager_ui <- function(id) {
 #' @rdname state_manager_module
 #' @keywords internal
 #'
-state_manager_srv <- function(id, slices_global, mapping_matrix, filtered_data_list, snapshot_history) {
+state_manager_srv <- function(id) {
   checkmate::assert_character(id)
-  checkmate::assert_true(is.reactive(slices_global))
-  checkmate::assert_class(isolate(slices_global()), "teal_slices")
-  checkmate::assert_true(is.reactive(mapping_matrix))
-  checkmate::assert_data_frame(isolate(mapping_matrix()), null.ok = TRUE)
-  checkmate::assert_list(filtered_data_list, types = "FilteredData", any.missing = FALSE, names = "named")
-  checkmate::assert_true(is.reactive(snapshot_history))
-  checkmate::assert_list(isolate(snapshot_history()), names = "unique")
 
   moduleServer(id, function(input, output, session) {
     ns <- session$ns
     sesh <- get_master_session()
 
-    # Store input states.
-    grab_history <- reactiveVal({
-      list()
-    })
+    # Retrieve global objects ----
+    slices_global <- GS$set_global("slices_global")
+    filtered_data_list <- GS$set_global("filtered_data_list")
+    mapping_matrix <- GS$set_global("mapping_matrix")
+    snapshot_history <- GS$set_global("snapshot_history")
+
+    # Register setter for global grab history ----
+    GS$add_setter("grab_history", setter_grab_history)
+
+    # Store global filter states ----
+    grab_history <- GS$set_global("grab_history")
 
     sesh$onBookmark(function(state) {
       # Add current filter state to bookmark.
@@ -169,3 +169,19 @@ get_master_session <- function() {
     app_session
   }
 }
+
+
+
+# setter for global variable ----
+#' @keywords internal
+#' @noRd
+setter_grab_history <- function() {
+  sesh <- getDefaultReactiveDomain()
+  if (is.null(sesh$userData$grab_history)) {
+    sesh$userData$grab_history <- reactiveVal({
+      list()
+    })
+  } else {
+    sesh$userData$grab_history
+  }
+}