diff --git a/R/layer.R b/R/layer.R
index c214b08..15afede 100644
--- a/R/layer.R
+++ b/R/layer.R
@@ -10,13 +10,16 @@
 #'
 #' @export
 Layer <- function(type, id, source = NULL, paint = NULL, layout = NULL, ...) {
-  list(
-    type = type,
-    id = id,
-    source = source,
-    paint = paint,
-    layout = layout
-  ) |>
+  types <- list(type = is.character, id = is.character, source = is.list, paint = is.list, layout = is.list)
+  c(rdantic(
+    list(
+      type = type,
+      id = id,
+      source = source,
+      paint = paint,
+      layout = layout
+    ), types
+  ), ...) |>
     purrr::compact() |>
     set_maplibre_class("MapLibreLayer")
 }
@@ -44,7 +47,7 @@ add_layer <- function(.map, layer) {
 #' @export
 #'
 #' @example examples/layers.R
-add_popup <- function(.map, layer_id, prop){
+add_popup <- function(.map, layer_id, prop) {
   .map |> add_call("addPopup", layer_id, prop)
 }
 
@@ -60,6 +63,6 @@ add_popup <- function(.map, layer_id, prop){
 #'
 #' @examples
 #' @example examples/layers.R
-add_tooltip <- function(.map, layer_id, prop){
+add_tooltip <- function(.map, layer_id, prop) {
   .map |> add_call("addTooltip", layer_id, prop)
 }
diff --git a/R/utils.R b/R/utils.R
index e5a170f..e6e9f13 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -2,3 +2,15 @@ set_maplibre_class <- function(.obj, class_name) {
   class(.obj) <- c(class(.obj), class_name)
   return(.obj)
 }
+
+rdantic <- function(.obj, types, test = 1L) {
+  for (k in names(.obj)) {
+    type_check <- types[[k]]
+    value <- .obj[[k]]
+    if (xor(!type_check(value), is.null(value))) {
+      stop(value, " is not ", deparse(substitute(type_check)) , call.=FALSE)
+    }
+  }
+
+  return(.obj)
+}
diff --git a/tests/testthat/test-rdantic.R b/tests/testthat/test-rdantic.R
new file mode 100644
index 0000000..0ed6226
--- /dev/null
+++ b/tests/testthat/test-rdantic.R
@@ -0,0 +1,12 @@
+test_that("rdantic", {
+  # Prepare
+  l <- list(a = 1, b = "test", d = NULL)
+  types <- list(a = is.numeric, b = is.character, d = is.numeric)
+
+  # Act
+  l <- rdantic(l, types)
+
+  # Assert
+  expect_equal(l$a, 1)
+  expect_equal(l$b, "test")
+})