diff --git a/.github/workflows/test-python.yml b/.github/workflows/test-python.yml
index 455f398..dc1ef36 100644
--- a/.github/workflows/test-python.yml
+++ b/.github/workflows/test-python.yml
@@ -44,7 +44,7 @@ jobs:
     strategy:
       fail-fast: true
       matrix:
-        python-version: ["3.11", "3.12"]
+        python-version: ["3.9", "3.10", "3.11", "3.12"]
     steps:
       - uses: actions/checkout@v4
 
diff --git a/pyproject.toml b/pyproject.toml
index 9027922..e0ebf72 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,7 +6,7 @@ license = "MIT"
 readme = "README.md"
 authors = [{ name = "Kyle Barron", email = "kyle@developmentseed.org" }]
 requires-python = ">=3.9"
-dependencies = []
+dependencies = ["typing-extensions; python_version < '3.12'"]
 keywords = []
 classifiers = [
     "Development Status :: 4 - Beta",
diff --git a/src/obspec/_attributes.py b/src/obspec/_attributes.py
index 783fc91..13be30b 100644
--- a/src/obspec/_attributes.py
+++ b/src/obspec/_attributes.py
@@ -1,17 +1,23 @@
 from __future__ import annotations
 
-from typing import Literal, TypeAlias
+import sys
+from typing import Literal, Union
 
-Attribute: TypeAlias = (
+if sys.version_info >= (3, 10):
+    from typing import TypeAlias
+else:
+    from typing_extensions import TypeAlias
+
+Attribute: TypeAlias = Union[
     Literal[
         "Content-Disposition",
         "Content-Encoding",
         "Content-Language",
         "Content-Type",
         "Cache-Control",
-    ]
-    | str
-)
+    ],
+    str,
+]
 """Additional object attribute types.
 
 - `"Content-Disposition"`: Specifies how the object should be handled by a browser.
diff --git a/src/obspec/_get.py b/src/obspec/_get.py
index 301f712..083fa6f 100644
--- a/src/obspec/_get.py
+++ b/src/obspec/_get.py
@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Protocol, Self, TypedDict
+from typing import TYPE_CHECKING, Protocol, TypedDict
 
 if TYPE_CHECKING:
     import sys
@@ -10,6 +10,11 @@
     from ._attributes import Attributes
     from ._meta import ObjectMeta
 
+    if sys.version_info >= (3, 11):
+        from typing import Self
+    else:
+        from typing_extensions import Self
+
     if sys.version_info >= (3, 12):
         from collections.abc import Buffer
     else:
diff --git a/src/obspec/_list.py b/src/obspec/_list.py
index 061aab9..04e2d9b 100644
--- a/src/obspec/_list.py
+++ b/src/obspec/_list.py
@@ -1,19 +1,17 @@
 from __future__ import annotations
 
+import sys
 from collections.abc import Sequence
-from typing import (
-    Generic,
-    Literal,
-    Protocol,
-    Self,
-    TypedDict,
-    TypeVar,
-    overload,
-)
+from typing import Generic, Literal, Protocol, TypedDict, TypeVar, overload
 
 from ._meta import ObjectMeta
 from .arrow import ArrowArrayExportable, ArrowStreamExportable
 
+if sys.version_info >= (3, 11):
+    from typing import Self
+else:
+    from typing_extensions import Self
+
 ListChunkType_co = TypeVar(
     "ListChunkType_co",
     Sequence[ObjectMeta],
diff --git a/src/obspec/_put.py b/src/obspec/_put.py
index f8bdc00..c16a9db 100644
--- a/src/obspec/_put.py
+++ b/src/obspec/_put.py
@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import IO, TYPE_CHECKING, Literal, Protocol, TypeAlias, TypedDict
+from typing import IO, TYPE_CHECKING, Literal, Protocol, TypedDict, Union
 
 if TYPE_CHECKING:
     import sys
@@ -9,6 +9,11 @@
 
     from ._attributes import Attributes
 
+    if sys.version_info >= (3, 10):
+        from typing import TypeAlias
+    else:
+        from typing_extensions import TypeAlias
+
     if sys.version_info >= (3, 12):
         from collections.abc import Buffer
     else:
@@ -32,7 +37,7 @@ class UpdateVersion(TypedDict, total=False):
     """A version indicator for the newly created object."""
 
 
-PutMode: TypeAlias = Literal["create", "overwrite"] | UpdateVersion
+PutMode: TypeAlias = Union[Literal["create", "overwrite"], UpdateVersion]
 """Configure preconditions for the put operation
 
 There are three modes:
diff --git a/uv.lock b/uv.lock
index ac329bc..7d03ca3 100644
--- a/uv.lock
+++ b/uv.lock
@@ -918,6 +918,9 @@ wheels = [
 name = "obspec"
 version = "0.1.0b4"
 source = { editable = "." }
+dependencies = [
+    { name = "typing-extensions", marker = "python_full_version < '3.12'" },
+]
 
 [package.dev-dependencies]
 dev = [
@@ -936,6 +939,7 @@ dev = [
 ]
 
 [package.metadata]
+requires-dist = [{ name = "typing-extensions", marker = "python_full_version < '3.12'" }]
 
 [package.metadata.requires-dev]
 dev = [