diff --git a/docs/changelog/3343.misc.rst b/docs/changelog/3343.misc.rst
new file mode 100644
index 0000000000..1f8e3bedc5
--- /dev/null
+++ b/docs/changelog/3343.misc.rst
@@ -0,0 +1 @@
+Prepare ``Loader`` and ``MemoryLoader`` for TOML support - by :user:`ziima`
diff --git a/src/tox/config/loader/memory.py b/src/tox/config/loader/memory.py
index 59d47bd77d..fb9182d09e 100644
--- a/src/tox/config/loader/memory.py
+++ b/src/tox/config/loader/memory.py
@@ -5,7 +5,7 @@
 
 from tox.config.types import Command, EnvList
 
-from .api import Loader
+from .api import Loader, Override
 from .section import Section
 from .str_convert import StrConvert
 
@@ -14,9 +14,16 @@
 
 
 class MemoryLoader(Loader[Any]):
-    def __init__(self, **kwargs: Any) -> None:
-        super().__init__(Section(prefix="<memory>", name=str(id(self))), [])
-        self.raw: dict[str, Any] = {**kwargs}
+    def __init__(
+        self,
+        raw: dict[str, Any],
+        *,
+        section: Section | None = None,
+        overrides: list[Override] | None = None,
+    ) -> None:
+        section = section or Section(prefix="<memory>", name=str(id(self)))
+        super().__init__(section, overrides or [])
+        self.raw = raw
 
     def load_raw(self, key: Any, conf: Config | None, env_name: str | None) -> Any:  # noqa: ARG002
         return self.raw[key]
diff --git a/src/tox/provision.py b/src/tox/provision.py
index 9e1e2bf8c8..e19bf21872 100644
--- a/src/tox/provision.py
+++ b/src/tox/provision.py
@@ -91,12 +91,14 @@ def add_tox_requires_min_version(reqs: list[Requirement]) -> list[Requirement]:
 
     deps = ", ".join(f"{p}{'' if v is None else f' ({v})'}" for p, v in missing)
     loader = MemoryLoader(  # these configuration values are loaded from in-memory always (no file conf)
-        base=[],  # disable inheritance for provision environments
-        package="skip",  # no packaging for this please
-        # use our own dependency specification
-        deps=PythonDeps("\n".join(str(r) for r in requires), root=state.conf.core["tox_root"]),
-        pass_env=["*"],  # do not filter environment variables, will be handled by provisioned tox
-        recreate=state.conf.options.recreate and not state.conf.options.no_recreate_provision,
+        {
+            "base": [],  # disable inheritance for provision environments
+            "package": "skip",  # no packaging for this please
+            # use our own dependency specification
+            "deps": PythonDeps("\n".join(str(r) for r in requires), root=state.conf.core["tox_root"]),
+            "pass_env": ["*"],  # do not filter environment variables, will be handled by provisioned tox
+            "recreate": state.conf.options.recreate and not state.conf.options.no_recreate_provision,
+        }
     )
     provision_tox_env: str = state.conf.core["provision_tox_env"]
     state.conf.memory_seed_loaders[provision_tox_env].append(loader)
diff --git a/src/tox/session/cmd/devenv.py b/src/tox/session/cmd/devenv.py
index c4754e5460..c5e11c2573 100644
--- a/src/tox/session/cmd/devenv.py
+++ b/src/tox/session/cmd/devenv.py
@@ -35,8 +35,10 @@ def devenv(state: State) -> int:
     opt.skip_pkg_install = False  # always install a package in this case
     opt.no_test = True  # do not run the test phase
     loader = MemoryLoader(  # these configuration values are loaded from in-memory always (no file conf)
-        usedevelop=True,  # dev environments must be of type dev
-        env_dir=opt.devenv_path,  # move it in source
+        {
+            "usedevelop": True,  # dev environments must be of type dev
+            "env_dir": opt.devenv_path,  # move it in source
+        }
     )
     state.conf.memory_seed_loaders[next(iter(opt.env))].append(loader)
 
diff --git a/src/tox/session/cmd/exec_.py b/src/tox/session/cmd/exec_.py
index 4ce3e947e4..3f94b53f70 100644
--- a/src/tox/session/cmd/exec_.py
+++ b/src/tox/session/cmd/exec_.py
@@ -34,9 +34,11 @@ def exec_(state: State) -> int:
         msg = f"exactly one target environment allowed in exec mode but found {', '.join(envs)}"
         raise HandledError(msg)
     loader = MemoryLoader(  # these configuration values are loaded from in-memory always (no file conf)
-        commands_pre=[],
-        commands=[],
-        commands_post=[],
+        {
+            "commands_pre": [],
+            "commands": [],
+            "commands_post": [],
+        }
     )
     conf = state.envs[envs[0]].conf
     conf.loaders.insert(0, loader)
diff --git a/src/tox/session/cmd/legacy.py b/src/tox/session/cmd/legacy.py
index a78d8bac78..05f122e2d4 100644
--- a/src/tox/session/cmd/legacy.py
+++ b/src/tox/session/cmd/legacy.py
@@ -129,7 +129,7 @@ def _handle_legacy_only_flags(option: Parsed, envs: EnvSelector) -> None:  # noq
         for env in envs.iter(only_active=True, package=False):
             env_conf = envs[env].conf
             if override:
-                env_conf.loaders.insert(0, MemoryLoader(**override))
+                env_conf.loaders.insert(0, MemoryLoader(override))
             if set_env:
                 cast(SetEnv, env_conf["set_env"]).update(set_env, override=True)
             if forced:
diff --git a/tests/config/loader/test_memory_loader.py b/tests/config/loader/test_memory_loader.py
index dfe8f9b8d9..114e92c2b0 100644
--- a/tests/config/loader/test_memory_loader.py
+++ b/tests/config/loader/test_memory_loader.py
@@ -12,7 +12,7 @@
 
 
 def test_memory_loader_override() -> None:
-    loader = MemoryLoader(a=1)
+    loader = MemoryLoader({"a": 1})
     loader.overrides["a"] = [Override("a=2")]
     args = ConfigLoadArgs([], "name", None)
     loaded = loader.load("a", of_type=int, conf=None, factory=None, args=args)
@@ -48,7 +48,7 @@ def test_memory_loader_override() -> None:
     ],
 )
 def test_memory_loader(value: Any, of_type: type[Any], outcome: Any) -> None:
-    loader = MemoryLoader(a=value, kwargs={})
+    loader = MemoryLoader({"a": value, "kwargs": {}})
     args = ConfigLoadArgs([], "name", None)
     loaded = loader.load("a", of_type=of_type, conf=None, factory=None, args=args)
     assert loaded == outcome
@@ -68,18 +68,18 @@ def test_memory_loader(value: Any, of_type: type[Any], outcome: Any) -> None:
     ],
 )
 def test_memory_loader_fails_invalid(value: Any, of_type: type[Any], exception: Exception, msg: str) -> None:
-    loader = MemoryLoader(a=value, kwargs={})
+    loader = MemoryLoader({"a": value, "kwargs": {}})
     args = ConfigLoadArgs([], "name", None)
     with pytest.raises(exception, match=msg):  # type: ignore[call-overload]
         loader.load("a", of_type=of_type, conf=None, factory=None, args=args)
 
 
 def test_memory_found_keys() -> None:
-    loader = MemoryLoader(a=1, c=2)
+    loader = MemoryLoader({"a": 1, "c": 2})
     assert loader.found_keys() == {"a", "c"}
 
 
 def test_memory_loader_contains() -> None:
-    loader = MemoryLoader(a=1)
+    loader = MemoryLoader({"a": 1})
     assert "a" in loader
     assert "b" not in loader
diff --git a/tests/config/test_main.py b/tests/config/test_main.py
index 853ef9bb44..070702e71e 100644
--- a/tests/config/test_main.py
+++ b/tests/config/test_main.py
@@ -63,7 +63,7 @@ def test_config_overrides(tox_ini_conf: ToxIniCreator) -> None:
 
 def test_config_override_wins_memory_loader(tox_ini_conf: ToxIniCreator) -> None:
     main_conf = tox_ini_conf("[testenv]", override=[Override("testenv.c=ok")])
-    conf = main_conf.get_env("py", loaders=[MemoryLoader(c="something_else")])
+    conf = main_conf.get_env("py", loaders=[MemoryLoader({"c": "something_else"})])
     conf.add_config("c", of_type=str, default="d", desc="desc")
     assert conf["c"] == "ok"
 
diff --git a/tests/config/test_sets.py b/tests/config/test_sets.py
index 91aec92c15..5db2d7ee23 100644
--- a/tests/config/test_sets.py
+++ b/tests/config/test_sets.py
@@ -181,7 +181,7 @@ def test_do_not_allow_create_config_set(mocker: MockerFixture) -> None:
 
 def test_set_env_raises_on_non_str(mocker: MockerFixture) -> None:
     env_set = EnvConfigSet(mocker.create_autospec(Config), Section("a", "b"), "b")
-    env_set.loaders.insert(0, MemoryLoader(set_env=1))
+    env_set.loaders.insert(0, MemoryLoader({"set_env": 1}))
     with pytest.raises(TypeError, match="1"):
         assert env_set["set_env"]
 
diff --git a/tests/plugin/test_plugin.py b/tests/plugin/test_plugin.py
index 32a8e9fdc9..a066c65efb 100644
--- a/tests/plugin/test_plugin.py
+++ b/tests/plugin/test_plugin.py
@@ -131,7 +131,7 @@ def test_plugin_can_set_core_conf(
 ) -> None:
     @impl
     def tox_add_core_config(core_conf: CoreConfigSet, state: State) -> None:  # noqa: ARG001
-        core_conf.loaders.insert(0, MemoryLoader(**{dir_name: tmp_path}))
+        core_conf.loaders.insert(0, MemoryLoader({dir_name: tmp_path}))
 
     register_inline_plugin(mocker, tox_add_core_config)
 
@@ -186,7 +186,7 @@ def tox_add_core_config(core_conf: CoreConfigSet, state: State) -> None:  # noqa
 def test_plugin_injects_invalid_python_run(tox_project: ToxProjectCreator, mocker: MockerFixture) -> None:
     @impl
     def tox_add_env_config(env_conf: EnvConfigSet, state: State) -> None:  # noqa: ARG001
-        env_conf.loaders.insert(0, MemoryLoader(deps=[1]))
+        env_conf.loaders.insert(0, MemoryLoader({"deps": [1]}))
         with pytest.raises(TypeError, match="1"):
             assert env_conf["deps"]