diff --git a/mapbox_vector_tile/encoder.py b/mapbox_vector_tile/encoder.py
index 955f189..157105d 100644
--- a/mapbox_vector_tile/encoder.py
+++ b/mapbox_vector_tile/encoder.py
@@ -27,6 +27,9 @@ def on_invalid_geometry_make_valid(shape):
 
 class VectorTile:
     def __init__(self, extents, on_invalid_geometry=None, max_geometry_validate_tries=5, check_winding_order=True):
+        if extents <= 0:
+            raise ValueError(f"The extents must be positive. {extents} provided.")
+
         self.tile = vector_tile.tile()
         self.extents = extents
         self.on_invalid_geometry = on_invalid_geometry
@@ -39,11 +42,17 @@ def __init__(self, extents, on_invalid_geometry=None, max_geometry_validate_trie
         self.seen_keys_idx = {}
         self.seen_values_idx = {}
         self.seen_values_bool_idx = {}
-
-    def add_features(self, features, layer_name="", quantize_bounds=None, y_coord_down=False):
+        self.seen_layer_names = set()
+
+    def add_features(self, features, layer_name, quantize_bounds=None, y_coord_down=False):
+        if not layer_name:
+            raise ValueError(f"A layer name can not be empty. {layer_name!r} was provided.")
+        if layer_name in self.seen_layer_names:
+            raise ValueError(f"The layer name {layer_name!r} already exists in the vector tile.")
+        self.seen_layer_names.add(layer_name)
         self.layer = self.tile.layers.add()
         self.layer.name = layer_name
-        self.layer.version = 1
+        self.layer.version = 2
         self.layer.extent = self.extents
 
         self.key_idx = 0
diff --git a/tests/test_encoder.py b/tests/test_encoder.py
index cc4d2e3..6b1158e 100644
--- a/tests/test_encoder.py
+++ b/tests/test_encoder.py
@@ -966,3 +966,61 @@ def test_issue_57(self):
         self.assertEqual(1, len(tile.layer.features))
         f = tile.layer.features[0]
         self.assertEqual(expected_commands, list(f.geometry))
+
+
+class InvalidVectorTileTest(unittest.TestCase):
+    def test_duplicate_layer_name(self):
+        from mapbox_vector_tile import encode
+
+        props = dict(foo="bar")
+        shape = "POINT(10 10)"
+        feature = dict(geometry=shape, properties=props)
+        features = [feature]
+        source = [dict(name="layername", features=features), dict(name="layername", features=features)]
+        with self.assertRaises(ValueError) as ex:
+            encode(source, extents=4096)
+        self.assertEqual(str(ex.exception), "The layer name 'layername' already exists in the vector tile.")
+
+    def test_empty_layer_name(self):
+        from mapbox_vector_tile import encode
+
+        props = dict(foo="bar")
+        shape = "POINT(10 10)"
+        feature = dict(geometry=shape, properties=props)
+        features = [feature]
+        source = [dict(name="", features=features)]
+        with self.assertRaises(ValueError) as ex:
+            encode(source, extents=4096)
+        self.assertEqual(str(ex.exception), "A layer name can not be empty. '' was provided.")
+
+        source = [dict(name=None, features=features)]
+        with self.assertRaises(ValueError) as ex:
+            encode(source, extents=4096)
+        self.assertEqual(str(ex.exception), "A layer name can not be empty. None was provided.")
+
+    def test_empty_layer(self):
+        from mapbox_vector_tile import encode
+
+        # No content
+        res = encode([], extents=4096)
+        self.assertEqual(res, b"")
+
+        # Layer without feature
+        res = encode(dict(name="layer", features=[]), extents=4096)
+        self.assertEqual(res, b"\x1a\x0c\n\x05layer(\x80 x\x02")
+
+    def test_invalid_extent(self):
+        from mapbox_vector_tile import encode
+
+        props = dict(foo="bar")
+        shape = "POINT(10 10)"
+        feature = dict(geometry=shape, properties=props)
+        features = [feature]
+        source = [dict(name="layername", features=features)]
+        with self.assertRaises(ValueError) as ex:
+            encode(source, extents=0)
+        self.assertEqual(str(ex.exception), "The extents must be positive. 0 provided.")
+
+        with self.assertRaises(ValueError) as ex:
+            encode(source, extents=-2.3)
+        self.assertEqual(str(ex.exception), "The extents must be positive. -2.3 provided.")