diff --git a/src/zarr/codecs/blosc.py b/src/zarr/codecs/blosc.py
index 2fcc041a6b..15869ebfde 100644
--- a/src/zarr/codecs/blosc.py
+++ b/src/zarr/codecs/blosc.py
@@ -87,25 +87,25 @@ def parse_blocksize(data: JSON) -> int:
 class BloscCodec(BytesBytesCodec):
     is_fixed_size = False
 
-    typesize: int | None
+    typesize: int
     cname: BloscCname = BloscCname.zstd
     clevel: int = 5
-    shuffle: BloscShuffle | None = BloscShuffle.noshuffle
+    shuffle: BloscShuffle
     blocksize: int = 0
 
     def __init__(
         self,
         *,
-        typesize: int | None = None,
+        typesize: int,
         cname: BloscCname | str = BloscCname.zstd,
         clevel: int = 5,
-        shuffle: BloscShuffle | str | None = None,
+        shuffle: BloscShuffle | str,
         blocksize: int = 0,
     ) -> None:
-        typesize_parsed = parse_typesize(typesize) if typesize is not None else None
+        typesize_parsed = parse_typesize(typesize)
         cname_parsed = parse_enum(cname, BloscCname)
         clevel_parsed = parse_clevel(clevel)
-        shuffle_parsed = parse_enum(shuffle, BloscShuffle) if shuffle is not None else None
+        shuffle_parsed = parse_enum(shuffle, BloscShuffle)
         blocksize_parsed = parse_blocksize(blocksize)
 
         object.__setattr__(self, "typesize", typesize_parsed)
@@ -120,10 +120,6 @@ def from_dict(cls, data: dict[str, JSON]) -> Self:
         return cls(**configuration_parsed)  # type: ignore[arg-type]
 
     def to_dict(self) -> dict[str, JSON]:
-        if self.typesize is None:
-            raise ValueError("`typesize` needs to be set for serialization.")
-        if self.shuffle is None:
-            raise ValueError("`shuffle` needs to be set for serialization.")
         return {
             "name": "blosc",
             "configuration": {
@@ -141,17 +137,11 @@ def evolve_from_array_spec(self, array_spec: ArraySpec) -> Self:
         if new_codec.typesize is None:
             new_codec = replace(new_codec, typesize=dtype.itemsize)
         if new_codec.shuffle is None:
-            new_codec = replace(
-                new_codec,
-                shuffle=(BloscShuffle.bitshuffle if dtype.itemsize == 1 else BloscShuffle.shuffle),
-            )
-
+            new_codec = replace(new_codec,shuffle=(BloscShuffle.bitshuffle if dtype.itemsize == 1 else BloscShuffle.shuffle),)
         return new_codec
 
     @cached_property
     def _blosc_codec(self) -> Blosc:
-        if self.shuffle is None:
-            raise ValueError("`shuffle` needs to be set for decoding and encoding.")
         map_shuffle_str_to_int = {
             BloscShuffle.noshuffle: 0,
             BloscShuffle.shuffle: 1,
diff --git a/src/zarr/codecs/bytes.py b/src/zarr/codecs/bytes.py
index 78c7b22fbc..f223c39094 100644
--- a/src/zarr/codecs/bytes.py
+++ b/src/zarr/codecs/bytes.py
@@ -34,26 +34,22 @@ class Endian(Enum):
 class BytesCodec(ArrayBytesCodec):
     is_fixed_size = True
 
-    endian: Endian | None
+    endian: Endian
 
-    def __init__(self, *, endian: Endian | str | None = default_system_endian) -> None:
-        endian_parsed = None if endian is None else parse_enum(endian, Endian)
+    def __init__(self, *, endian: Endian | str = default_system_endian) -> None:
+        endian_parsed = parse_enum(endian, Endian)
 
         object.__setattr__(self, "endian", endian_parsed)
 
     @classmethod
     def from_dict(cls, data: dict[str, JSON]) -> Self:
         _, configuration_parsed = parse_named_configuration(
-            data, "bytes", require_configuration=False
+            data, "bytes", require_configuration=True
         )
-        configuration_parsed = configuration_parsed or {}
         return cls(**configuration_parsed)  # type: ignore[arg-type]
 
     def to_dict(self) -> dict[str, JSON]:
-        if self.endian is None:
-            return {"name": "bytes"}
-        else:
-            return {"name": "bytes", "configuration": {"endian": self.endian.value}}
+        return {"name": "bytes", "configuration": {"endian": self.endian.value}}
 
     def evolve_from_array_spec(self, array_spec: ArraySpec) -> Self:
         if array_spec.dtype.itemsize == 0:
@@ -104,7 +100,6 @@ async def _encode_single(
         assert isinstance(chunk_array, NDBuffer)
         if (
             chunk_array.dtype.itemsize > 1
-            and self.endian is not None
             and self.endian != chunk_array.byteorder
         ):
             # type-ignore is a numpy bug