diff --git a/src/speechify/client.py b/src/speechify/client.py
index 4c47cb4..65bd7c5 100644
--- a/src/speechify/client.py
+++ b/src/speechify/client.py
@@ -71,7 +71,7 @@ def __init__(
         base_url: typing.Optional[str] = None,
         environment: SpeechifyEnvironment = SpeechifyEnvironment.DEFAULT,
         version: typing.Optional[str] = "2026-09-13",
-        token: typing.Optional[typing.Union[str, typing.Callable[[], str]]] = os.getenv("SPEECHIFY_API_KEY"),
+        token: typing.Optional[typing.Union[str, typing.Callable[[], str]]] = None,
         headers: typing.Optional[typing.Dict[str, str]] = None,
         timeout: typing.Optional[float] = None,
         max_retries: typing.Optional[int] = None,
@@ -83,6 +83,8 @@ def __init__(
             timeout if timeout is not None else 60 if httpx_client is None else httpx_client.timeout.read
         )
         _defaulted_max_retries = max_retries if max_retries is not None else 2
+        if token is None:
+            token = os.getenv("SPEECHIFY_API_KEY")
         if token is None:
             raise ApiError(
                 body="The client must be instantiated be either passing in token or setting SPEECHIFY_API_KEY"
@@ -205,7 +207,7 @@ def __init__(
         base_url: typing.Optional[str] = None,
         environment: SpeechifyEnvironment = SpeechifyEnvironment.DEFAULT,
         version: typing.Optional[str] = "2026-09-13",
-        token: typing.Optional[typing.Union[str, typing.Callable[[], str]]] = os.getenv("SPEECHIFY_API_KEY"),
+        token: typing.Optional[typing.Union[str, typing.Callable[[], str]]] = None,
         headers: typing.Optional[typing.Dict[str, str]] = None,
         async_token: typing.Optional[typing.Callable[[], typing.Awaitable[str]]] = None,
         timeout: typing.Optional[float] = None,
@@ -218,6 +220,8 @@ def __init__(
             timeout if timeout is not None else 60 if httpx_client is None else httpx_client.timeout.read
         )
         _defaulted_max_retries = max_retries if max_retries is not None else 2
+        if token is None:
+            token = os.getenv("SPEECHIFY_API_KEY")
         if token is None:
             raise ApiError(
                 body="The client must be instantiated be either passing in token or setting SPEECHIFY_API_KEY"
diff --git a/tests/custom/test_environment_token.py b/tests/custom/test_environment_token.py
new file mode 100644
index 0000000..bd5e37b
--- /dev/null
+++ b/tests/custom/test_environment_token.py
@@ -0,0 +1,66 @@
+import importlib
+from typing import Any
+
+import httpx
+import pytest
+
+import speechify.client as client_module
+from speechify.core.api_error import ApiError
+
+
+@pytest.fixture
+def imported_without_key(monkeypatch):
+    monkeypatch.delenv("SPEECHIFY_API_KEY", raising=False)
+    importlib.reload(client_module)
+    yield client_module
+    # Avoid leaving reloaded import-time defaults behind for other test files.
+    monkeypatch.undo()
+    importlib.reload(client_module)
+
+
+@pytest.mark.parametrize("mode", ["sync", "async"])
+@pytest.mark.parametrize("scenario", ["late", "rotated", "removed", "explicit", "callable", "missing"])
+async def test_token_is_resolved_when_each_client_is_created(imported_without_key, monkeypatch, mode, scenario):
+    module = imported_without_key
+    if scenario in {"rotated", "removed"}:
+        monkeypatch.setenv("SPEECHIFY_API_KEY", "old-key")
+        importlib.reload(module)
+    if scenario in {"removed", "missing"}:
+        monkeypatch.delenv("SPEECHIFY_API_KEY", raising=False)
+    else:
+        monkeypatch.setenv("SPEECHIFY_API_KEY", "current-key")
+
+    seen = []
+
+    def respond(request):
+        seen.append(request.headers["Authorization"])
+        return httpx.Response(200, json={"models": [], "dialogue_models": []})
+
+    kwargs: dict[str, Any] = {}
+    if scenario == "explicit":
+        kwargs["token"] = "explicit-key"
+    elif scenario == "callable":
+        kwargs["token"] = lambda: "callable-key"
+
+    transport = httpx.MockTransport(respond)
+    if mode == "sync":
+        with httpx.Client(transport=transport) as http_client:
+            if scenario in {"removed", "missing"}:
+                with pytest.raises(ApiError):
+                    module.Speechify(httpx_client=http_client, **kwargs)
+                assert not seen
+                return
+            client = module.Speechify(httpx_client=http_client, **kwargs)
+            client.models.list()
+    else:
+        async with httpx.AsyncClient(transport=transport) as http_client:
+            if scenario in {"removed", "missing"}:
+                with pytest.raises(ApiError):
+                    module.AsyncSpeechify(httpx_client=http_client, **kwargs)
+                assert not seen
+                return
+            client = module.AsyncSpeechify(httpx_client=http_client, **kwargs)
+            await client.models.list()
+
+    expected = {"explicit": "explicit-key", "callable": "callable-key"}.get(scenario, "current-key")
+    assert seen == [f"Bearer {expected}"]