diff --git a/lit_nlp/app.py b/lit_nlp/app.py
index 2ce66896..a83eabb7 100644
--- a/lit_nlp/app.py
+++ b/lit_nlp/app.py
@@ -899,11 +899,7 @@ def __init__(
         id_hash_fn=caching.input_hash,
     )
 
-    # TODO(lit-dev): override layouts instead of merging, to allow clients
-    # to opt-out of the default bundled layouts. This will require updating
-    # client code to manually merge when this is the desired behavior.
-    self._layouts = dict(layout.DEFAULT_LAYOUTS, **(layouts or {}))
-
+    self._layouts = layouts if layouts else layout.DEFAULT_LAYOUTS
     self._model_loaders: ModelLoadersMap = model_loaders or {}
     self._models: dict[str, caching.CachingModelWrapper] = {}
     for name, model in models.items():
diff --git a/lit_nlp/examples/coref/coref_demo.py b/lit_nlp/examples/coref/coref_demo.py
index cb395b17..95ff9549 100644
--- a/lit_nlp/examples/coref/coref_demo.py
+++ b/lit_nlp/examples/coref/coref_demo.py
@@ -123,7 +123,8 @@
     },
     description="Custom layout for the Winogender coreference demo.",
 )
-CUSTOM_LAYOUTS = {"winogender": WINOGENDER_LAYOUT}
+
+CUSTOM_LAYOUTS = layout.DEFAULT_LAYOUTS | {"winogender": WINOGENDER_LAYOUT}
 
 FLAGS.set_default("default_layout", "winogender")
 
diff --git a/lit_nlp/examples/custom_module/potato_demo.py b/lit_nlp/examples/custom_module/potato_demo.py
index 25c6b17a..de580f54 100644
--- a/lit_nlp/examples/custom_module/potato_demo.py
+++ b/lit_nlp/examples/custom_module/potato_demo.py
@@ -57,6 +57,8 @@
     description="Custom layout with our spud-tastic potato module.",
 )
 
+CUSTOM_LAYOUTS = layout.DEFAULT_LAYOUTS | {"potato": POTATO_LAYOUT}
+
 
 def get_wsgi_app() -> Optional[dev_server.LitServerType]:
   """Returns a LitApp instance for consumption by gunicorn."""
@@ -88,7 +90,7 @@ def main(argv: Sequence[str]) -> Optional[dev_server.LitServerType]:
   lit_demo = dev_server.Server(
       models,
       datasets,
-      layouts={"potato": POTATO_LAYOUT},
+      layouts=CUSTOM_LAYOUTS,
       **server_flags.get_flags())
   return lit_demo.serve()
 
diff --git a/lit_nlp/examples/dalle/demo.py b/lit_nlp/examples/dalle/demo.py
index 1a466d4b..ea049178 100644
--- a/lit_nlp/examples/dalle/demo.py
+++ b/lit_nlp/examples/dalle/demo.py
@@ -58,7 +58,8 @@
     },
     description="Custom layout for Text to Image models.",
 )
-_CUSTOM_LAYOUTS = {"DALLE_LAYOUT": _DALLE_LAYOUT}
+
+CUSTOM_LAYOUTS = layout.DEFAULT_LAYOUTS | {"DALLE_LAYOUT": _DALLE_LAYOUT}
 
 
 def get_wsgi_app() -> Optional[dev_server.LitServerType]:
@@ -92,7 +93,7 @@ def main(argv: Sequence[str]) -> Optional[dev_server.LitServerType]:
   lit_demo = dev_server.Server(
       models,
       datasets,
-      layouts=_CUSTOM_LAYOUTS,
+      layouts=CUSTOM_LAYOUTS,
       **server_flags.get_flags(),
   )
   return lit_demo.serve()
diff --git a/lit_nlp/examples/image_demo.py b/lit_nlp/examples/image_demo.py
index 459ef6d6..5d9d25a4 100644
--- a/lit_nlp/examples/image_demo.py
+++ b/lit_nlp/examples/image_demo.py
@@ -66,6 +66,8 @@ def get_wsgi_app():
     description='Basic layout for image demo',
 )
 
+CUSTOM_LAYOUTS = layout.DEFAULT_LAYOUTS | {'default': DEMO_LAYOUT}
+
 
 def main(argv: Sequence[str]) -> Optional[dev_server.LitServerType]:
   if len(argv) > 1:
diff --git a/lit_nlp/examples/is_eval/is_eval_demo.py b/lit_nlp/examples/is_eval/is_eval_demo.py
index b75abe65..0621adef 100644
--- a/lit_nlp/examples/is_eval/is_eval_demo.py
+++ b/lit_nlp/examples/is_eval/is_eval_demo.py
@@ -91,7 +91,7 @@
         ],
     },
     description="Custom layout for evaluating input salience methods.")
-CUSTOM_LAYOUTS = {"is_eval": IS_EVAL_LAYOUT}
+CUSTOM_LAYOUTS = layout.DEFAULT_LAYOUTS | {"is_eval": IS_EVAL_LAYOUT}
 # You can change this back via URL param, e.g. localhost:5432/?layout=default
 FLAGS.set_default("default_layout", "is_eval")
 
diff --git a/lit_nlp/examples/lm_demo.py b/lit_nlp/examples/lm_demo.py
index b1cef5ab..928f423b 100644
--- a/lit_nlp/examples/lm_demo.py
+++ b/lit_nlp/examples/lm_demo.py
@@ -86,7 +86,8 @@
     },
     description="Custom layout for language models.",
 )
-CUSTOM_LAYOUTS = {"lm": LM_LAYOUT}
+
+CUSTOM_LAYOUTS = dict(layout.DEFAULT_LAYOUTS, **{"lm": LM_LAYOUT})
 
 # You can also change this via URL param e.g. localhost:5432/?layout=default
 FLAGS.set_default("default_layout", "lm")
diff --git a/lit_nlp/examples/penguin_demo.py b/lit_nlp/examples/penguin_demo.py
index 109f9ea9..79cc077c 100644
--- a/lit_nlp/examples/penguin_demo.py
+++ b/lit_nlp/examples/penguin_demo.py
@@ -49,7 +49,7 @@
     lower=layout.STANDARD_LAYOUT.lower,
     description='Custom layout for the Palmer Penguins demo.',
 )
-CUSTOM_LAYOUTS = {'penguins': PENGUIN_LAYOUT}
+CUSTOM_LAYOUTS = layout.DEFAULT_LAYOUTS | {'penguins': PENGUIN_LAYOUT}
 
 
 # Function for running demo through gunicorn instead of the local dev server.