diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 62a9b0dd..48f06ac9 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -32,6 +32,7 @@ jobs:
         uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
+          cache: pip
 
       - id: dependencies
         run: |
@@ -69,6 +70,7 @@ jobs:
         uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
+          cache: pip
 
       - id: dependencies
         run: |
diff --git a/rohmu/__init__.py b/rohmu/__init__.py
index 7064802f..172a07b0 100644
--- a/rohmu/__init__.py
+++ b/rohmu/__init__.py
@@ -11,12 +11,52 @@
 from .factory import (
     Config,
     get_class_for_notifier,
+    get_class_for_storage_driver,
     get_class_for_transfer,
     get_notifier,
     get_transfer,
+    get_transfer_from_model,
     get_transfer_model,
     NOTIFIER_TYPE,
     STORAGE_TYPE,
 )
 from .notifier.interface import Notifier
 from rohmu.object_storage.base import BaseTransfer
+from rohmu.object_storage.config import (
+    AzureObjectStorageConfig,
+    GoogleObjectStorageConfig,
+    LocalObjectStorageConfig,
+    ProxyInfo,
+    S3AddressingStyle,
+    S3ObjectStorageConfig,
+    SFTPObjectStorageConfig,
+    StorageDriver,
+    SwiftObjectStorageConfig,
+)
+
+__all__ = [
+    "AzureObjectStorageConfig",
+    "BaseTransfer",
+    "Config",
+    "get_class_for_notifier",
+    "get_class_for_storage_driver",
+    "get_class_for_transfer",
+    "get_notifier",
+    "get_transfer_from_model",
+    "get_transfer_model",
+    "get_transfer",
+    "GoogleObjectStorageConfig",
+    "InvalidConfigurationError",
+    "IO_BLOCK_SIZE",
+    "LocalObjectStorageConfig",
+    "NOTIFIER_TYPE",
+    "Notifier",
+    "ProxyInfo",
+    "S3AddressingStyle",
+    "S3ObjectStorageConfig",
+    "SFTPObjectStorageConfig",
+    "STORAGE_TYPE",
+    "StorageDriver",
+    "StorageModel",
+    "SwiftObjectStorageConfig",
+]
diff --git a/rohmu/common/models.py b/rohmu/common/models.py
index 2586b7a9..c6d340cd 100644
--- a/rohmu/common/models.py
+++ b/rohmu/common/models.py
@@ -1,7 +1,6 @@
 # Copyright (c) 2023 Aiven, Helsinki, Finland. https://aiven.io/
 from rohmu.common.statsd import StatsdConfig
 from rohmu.common.strenum import StrEnum
-from rohmu.notifier.interface import Notifier
 from typing import Optional
 
 import enum
@@ -73,7 +72,6 @@ class ProxyInfo(RohmuModel):
 
 class StorageModel(pydantic.BaseModel):
     storage_type: StorageDriver
-    notifier: Optional[Notifier] = None
     statsd_info: Optional[StatsdConfig] = None
 
     class Config:
diff --git a/rohmu/common/strenum.py b/rohmu/common/strenum.py
index 4ad7f72a..ed8da07b 100644
--- a/rohmu/common/strenum.py
+++ b/rohmu/common/strenum.py
@@ -6,6 +6,9 @@
 """
 from __future__ import annotations
 
+from typing import Optional
+from typing_extensions import Self
+
 import enum
 
 
@@ -14,7 +17,7 @@ def __str__(self) -> str:
         return str(self.value)
 
     @classmethod
-    def of(cls, value: str) -> StrEnum | None:
+    def of(cls, value: str) -> Optional[Self]:
         try:
             return cls(value)
         except ValueError:
diff --git a/rohmu/factory.py b/rohmu/factory.py
index 1bc91732..4b119c65 100644
--- a/rohmu/factory.py
+++ b/rohmu/factory.py
@@ -1,44 +1,48 @@
 # Copyright (c) 2023 Aiven, Helsinki, Finland. https://aiven.io/
 
-from .common.models import StorageModel
+from .common.models import StorageDriver, StorageModel
 from .errors import InvalidConfigurationError
 from .notifier.interface import Notifier
 from rohmu.object_storage.base import BaseTransfer
-from typing import Any, cast, Dict, Type
+from rohmu.object_storage.config import StorageModelT
+from typing import Any, Dict, Optional, Type
 
 STORAGE_TYPE = "storage_type"
 NOTIFIER_TYPE = "notifier_type"
 Config = Dict[str, Any]
 
 
-def get_class_for_transfer(obj_store: Config) -> Type[BaseTransfer[StorageModel]]:
-    storage_type = obj_store[STORAGE_TYPE]
-    if storage_type == "azure":
+def get_class_for_transfer(obj_store: Config) -> Type[BaseTransfer[Any]]:
+    return get_class_for_storage_driver(StorageDriver(obj_store[STORAGE_TYPE]))
+
+
+def get_class_for_storage_driver(storage_driver: StorageDriver) -> Type[BaseTransfer[Any]]:
+    if storage_driver == StorageDriver.azure:
         from rohmu.object_storage.azure import AzureTransfer
 
-        return cast(Type[BaseTransfer[StorageModel]], AzureTransfer)
-    elif storage_type == "google":
+        return AzureTransfer
+    elif storage_driver == StorageDriver.google:
         from rohmu.object_storage.google import GoogleTransfer
 
-        return cast(Type[BaseTransfer[StorageModel]], GoogleTransfer)
-    elif storage_type == "sftp":
+        return GoogleTransfer
+    elif storage_driver == StorageDriver.sftp:
         from rohmu.object_storage.sftp import SFTPTransfer
 
-        return cast(Type[BaseTransfer[StorageModel]], SFTPTransfer)
-    elif storage_type == "local":
+        return SFTPTransfer
+    elif storage_driver == StorageDriver.local:
         from rohmu.object_storage.local import LocalTransfer
 
-        return cast(Type[BaseTransfer[StorageModel]], LocalTransfer)
-    elif storage_type == "s3":
+        return LocalTransfer
+    elif storage_driver == StorageDriver.s3:
         from rohmu.object_storage.s3 import S3Transfer
 
-        return cast(Type[BaseTransfer[StorageModel]], S3Transfer)
-    elif storage_type == "swift":
+        return S3Transfer
+    elif storage_driver == StorageDriver.swift:
         from rohmu.object_storage.swift import SwiftTransfer
 
-        return cast(Type[BaseTransfer[StorageModel]], SwiftTransfer)
+        return SwiftTransfer
 
-    raise InvalidConfigurationError(f"unsupported storage type {repr(storage_type)}")
+    raise InvalidConfigurationError(f"unsupported storage type {storage_driver!r}")
 
 
 def get_class_for_notifier(notifier_config: Config) -> Type[Notifier]:
@@ -59,18 +63,17 @@ def get_notifier(notifier_config: Config) -> Notifier:
 
 def get_transfer_model(storage_config: Config) -> StorageModel:
     storage_class = get_class_for_transfer(storage_config)
-    storage_config = dict(storage_config)
-    storage_config.pop(STORAGE_TYPE)
-    notifier_config = storage_config.pop("notifier", None)
-    notifier = None
-    if notifier_config is not None:
-        notifier = get_notifier(notifier_config)
-
-    model = storage_class.config_model(**storage_config, notifier=notifier)
-    return model
+    return storage_class.config_model(**storage_config)
 
 
-def get_transfer(storage_config: Config) -> BaseTransfer[StorageModel]:
-    storage_class = get_class_for_transfer(storage_config)
+def get_transfer(storage_config: Config) -> BaseTransfer[Any]:
+    storage_config = storage_config.copy()
+    noitifier_config = storage_config.pop("notifier")
+    notifier = get_notifier(noitifier_config)
     model = get_transfer_model(storage_config)
-    return storage_class.from_model(model)
+    return get_transfer_from_model(model, notifier)
+
+
+def get_transfer_from_model(model: StorageModelT, notifier: Optional[Notifier] = None) -> BaseTransfer[StorageModelT]:
+    storage_class = get_class_for_storage_driver(model.storage_type)
+    return storage_class.from_model(model, notifier)
diff --git a/rohmu/object_storage/base.py b/rohmu/object_storage/base.py
index 9e9a13ce..33e39907 100644
--- a/rohmu/object_storage/base.py
+++ b/rohmu/object_storage/base.py
@@ -32,6 +32,7 @@
     TypeVar,
     Union,
 )
+from typing_extensions import Self
 
 import logging
 import os
@@ -130,8 +131,8 @@ def _should_multipart(
         return int(size) > chunk_size
 
     @classmethod
-    def from_model(cls, model: StorageModelT) -> BaseTransfer[StorageModelT]:
-        return cls(**model.dict(by_alias=True, exclude={"storage_type"}))
+    def from_model(cls, model: StorageModelT, notifier: Optional[Notifier] = None) -> Self:
+        return cls(**model.dict(by_alias=True, exclude={"storage_type"}), notifier=notifier)
 
     def copy_file(
         self, *, source_key: str, destination_key: str, metadata: Optional[Metadata] = None, **_kwargs: Any
diff --git a/rohmu/object_storage/s3.py b/rohmu/object_storage/s3.py
index 6daba0cf..8e09207c 100644
--- a/rohmu/object_storage/s3.py
+++ b/rohmu/object_storage/s3.py
@@ -59,7 +59,7 @@ def create_s3_client(
     aws_secret_access_key: Optional[str],
     aws_session_token: Optional[str],
     region_name: str,
-    verify: Optional[bool | str] = None,
+    verify: Optional[Union[bool, str]] = None,
     endpoint_url: Optional[str] = None,
 ) -> S3Client:
     s3_client = session.create_client(
diff --git a/rohmu/transfer_pool.py b/rohmu/transfer_pool.py
index 0292f2b9..41aa1b60 100644
--- a/rohmu/transfer_pool.py
+++ b/rohmu/transfer_pool.py
@@ -11,8 +11,10 @@
 from .factory import get_transfer as rohmu_get_transfer
 from contextlib import contextmanager
 from rohmu.common.models import StorageModel
+from rohmu.notifier.interface import Notifier
 from rohmu.object_storage.base import BaseTransfer
 from typing import Any, Callable, Generator, Optional
+from typing_extensions import Self
 
 import heapq
 import json
@@ -137,7 +139,7 @@ def __getattribute__(self, attr: str) -> Any:
         return super().__getattribute__(attr)
 
     @classmethod
-    def from_model(cls, model: StorageModel) -> BaseTransfer[StorageModel]:
+    def from_model(cls, model: StorageModel, notifier: Optional[Notifier] = None) -> Self:
         raise InvalidTransferError("You should not call class methods on SafeTransfer instances")
 
     def return_to_pool(self) -> None:
diff --git a/setup.cfg b/setup.cfg
index 96744eb8..3d91a225 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -23,6 +23,7 @@ platforms =
 package_dir =
     =.
 packages = find:
+python_requires = >=3.8
 install_requires =
     azure-storage-blob >= 2.1.0
     botocore
diff --git a/test/common/test_statsd.py b/test/common/test_statsd.py
index 2efec217..7a80dd85 100644
--- a/test/common/test_statsd.py
+++ b/test/common/test_statsd.py
@@ -10,7 +10,7 @@
 from __future__ import annotations
 
 from rohmu.common import statsd
-from typing import Any
+from typing import Any, Union
 
 import asyncio
 import pytest
@@ -21,7 +21,7 @@ class _Protocol(asyncio.DatagramProtocol):
     def __init__(self, queue: asyncio.Queue[bytes]):
         self.received_queue = queue
 
-    def datagram_received(self, data: bytes, addr: tuple[str | Any, int]) -> None:
+    def datagram_received(self, data: bytes, addr: tuple[Union[str, Any], int]) -> None:
         self.received_queue.put_nowait(data)
 
 
diff --git a/test/object_storage/test_s3.py b/test/object_storage/test_s3.py
index 38dc56ec..f09f31ce 100644
--- a/test/object_storage/test_s3.py
+++ b/test/object_storage/test_s3.py
@@ -13,7 +13,7 @@
 from rohmu.object_storage.config import S3ObjectStorageConfig
 from rohmu.object_storage.s3 import S3Transfer
 from tempfile import NamedTemporaryFile
-from typing import Any, BinaryIO, Callable, Iterator, Optional
+from typing import Any, BinaryIO, Callable, Iterator, Optional, Union
 from unittest.mock import ANY, call, MagicMock, patch
 
 import pytest
@@ -240,7 +240,7 @@ def test_validate_is_verify_tls_and_cert_path() -> None:
         (False, None, False),
     ],
 )
-def test_cert_path(is_verify_tls: bool, cert_path: Path | None, expected: str | bool) -> None:
+def test_cert_path(is_verify_tls: bool, cert_path: Optional[Path], expected: Union[str, bool]) -> None:
     with patch.object(rohmu.object_storage.s3, "create_s3_client") as mock:
         S3Transfer(
             region="test-region",
diff --git a/test/test_factory.py b/test/test_factory.py
index 32b181fc..a59fc643 100644
--- a/test/test_factory.py
+++ b/test/test_factory.py
@@ -1,7 +1,6 @@
-from rohmu.factory import Config, get_class_for_transfer, get_transfer
+from rohmu.factory import Config, get_class_for_transfer, get_transfer, get_transfer_from_model
 from rohmu.object_storage.config import S3ObjectStorageConfig
 from rohmu.object_storage.s3 import S3Transfer
-from typing import cast
 from unittest.mock import ANY, MagicMock, Mock, patch
 
 import pytest
@@ -42,18 +41,17 @@ def test_get_transfer_s3(
     config: Config,
 ) -> None:
     expected_config_arg = dict(config)
-    expected_config_arg.pop("storage_type")
     expected_config_arg.pop("notifier")
     expected_botocore_config = {"proxies": {"https": "socks5://bob:secret@proxy.test:16666"}}
-    mock_config_model.return_value = S3ObjectStorageConfig(**expected_config_arg, notifier=None)
+    mock_config_model.return_value = S3ObjectStorageConfig(**expected_config_arg)
 
     transfer_object = get_transfer(config)
 
-    mock_config_model.assert_called_once_with(**expected_config_arg, notifier=mock_notifier())
-    mock_from_model.assert_called_once_with(mock_config_model())
+    mock_config_model.assert_called_once_with(**expected_config_arg)
+    mock_from_model.assert_called_once_with(mock_config_model(), mock_notifier.return_value)
+    mock_notifier.assert_called_once_with(url=config["notifier"]["url"])
     assert isinstance(transfer_object, S3Transfer)
-    # cast was the easiest way to convince mypy
-    assert cast(S3Transfer, transfer_object).bucket_name == "dummy-bucket"
+    assert transfer_object.bucket_name == "dummy-bucket"
     mock_botocore_config.assert_called_once_with(**expected_botocore_config)
     mock_s3_client.assert_called_once_with(
         session=ANY,
@@ -70,3 +68,29 @@ def test_get_transfer_s3(
 @patch.dict(sys.modules, {"swiftclient": MagicMock(), "azure.common": MagicMock()})
 def test_config_model_defined(storage_type: str) -> None:
     assert get_class_for_transfer({"storage_type": storage_type}).config_model
+
+
+@patch("rohmu.object_storage.s3.create_s3_client")
+def test_get_transfer_from_model(
+    create_s3_client: Mock,
+) -> None:
+    config = S3ObjectStorageConfig(
+        region="dummy-region",
+        bucket_name="dummy-bucket",
+        proxy_info={
+            "host": "proxy.test",
+            "port": "16666",
+            "type": "socks5",
+            "user": "bob",
+            "pass": "secret",
+        },
+    )
+    get_transfer_from_model(config)
+    create_s3_client.assert_called_once_with(
+        session=ANY,
+        config=ANY,
+        aws_access_key_id=None,
+        aws_secret_access_key=None,
+        aws_session_token=None,
+        region_name="dummy-region",
+    )