diff --git a/src/dispatch/__init__.py b/src/dispatch/__init__.py
index 154257db..45a45e75 100644
--- a/src/dispatch/__init__.py
+++ b/src/dispatch/__init__.py
@@ -4,7 +4,7 @@
 
 import dispatch.integrations
 from dispatch.coroutine import all, any, call, gather, race
-from dispatch.function import DEFAULT_API_URL, Client
+from dispatch.function import DEFAULT_API_URL, Client, Registry
 from dispatch.id import DispatchID
 from dispatch.proto import Call, Error, Input, Output
 from dispatch.status import Status
@@ -23,4 +23,5 @@
     "all",
     "any",
     "race",
+    "Registry",
 ]
diff --git a/src/dispatch/fastapi.py b/src/dispatch/fastapi.py
index 97c4f7ed..0cb98384 100644
--- a/src/dispatch/fastapi.py
+++ b/src/dispatch/fastapi.py
@@ -115,8 +115,7 @@ def __init__(
                 "request verification is disabled because DISPATCH_VERIFICATION_KEY is not set"
             )
 
-        self.client = Client(api_key=api_key, api_url=api_url)
-        super().__init__(endpoint, self.client)
+        super().__init__(endpoint, api_key=api_key, api_url=api_url)
 
         function_service = _new_app(self, verification_key)
         app.mount("/dispatch.sdk.v1.FunctionService", function_service)
@@ -225,7 +224,7 @@ async def execute(request: fastapi.Request):
             raise _ConnectError(400, "invalid_argument", "function is required")
 
         try:
-            func = function_registry._functions[req.function]
+            func = function_registry.functions[req.function]
         except KeyError:
             logger.debug("function '%s' not found", req.function)
             raise _ConnectError(
diff --git a/src/dispatch/function.py b/src/dispatch/function.py
index 55277fa9..db14868a 100644
--- a/src/dispatch/function.py
+++ b/src/dispatch/function.py
@@ -100,7 +100,6 @@ def __init__(
         client: Client,
         name: str,
         primitive_func: PrimitiveFunctionType,
-        func: Callable,
     ):
         PrimitiveFunction.__init__(self, endpoint, client, name, primitive_func)
 
@@ -158,21 +157,30 @@ def build_call(
 
 
 class Registry:
-    """Registry of local functions."""
+    """Registry of functions."""
 
-    __slots__ = ("_functions", "_endpoint", "_client")
+    __slots__ = ("functions", "endpoint", "client")
 
-    def __init__(self, endpoint: str, client: Client):
-        """Initialize a local function registry.
+    def __init__(
+        self, endpoint: str, api_key: str | None = None, api_url: str | None = None
+    ):
+        """Initialize a function registry.
 
         Args:
             endpoint: URL of the endpoint that the function is accessible from.
-            client: Client for the Dispatch API. Used to dispatch calls to
-                local functions.
+
+            api_key: Dispatch API key to use for authentication when
+                dispatching calls to functions. Uses the value of the
+                DISPATCH_API_KEY environment variable by default.
+
+            api_url: The URL of the Dispatch API to use when dispatching calls
+                to functions. Uses the value of the DISPATCH_API_URL environment
+                variable if set, otherwise defaults to the public Dispatch API
+                (DEFAULT_API_URL).
         """
-        self._functions: Dict[str, PrimitiveFunction] = {}
-        self._endpoint = endpoint
-        self._client = client
+        self.functions: Dict[str, PrimitiveFunction] = {}
+        self.endpoint = endpoint
+        self.client = Client(api_key=api_key, api_url=api_url)
 
     @overload
     def function(self, func: Callable[P, Coroutine[Any, Any, T]]) -> Function[P, T]: ...
@@ -215,9 +223,7 @@ def primitive_func(input: Input) -> Output:
         primitive_func.__qualname__ = f"{name}_primitive"
         primitive_func = durable(primitive_func)
 
-        wrapped_func = Function[P, T](
-            self._endpoint, self._client, name, primitive_func, func
-        )
+        wrapped_func = Function[P, T](self.endpoint, self.client, name, primitive_func)
         self._register(name, wrapped_func)
         return wrapped_func
 
@@ -228,20 +234,20 @@ def primitive_function(
         name = primitive_func.__qualname__
         logger.info("registering primitive function: %s", name)
         wrapped_func = PrimitiveFunction(
-            self._endpoint, self._client, name, primitive_func
+            self.endpoint, self.client, name, primitive_func
         )
         self._register(name, wrapped_func)
         return wrapped_func
 
     def _register(self, name: str, wrapped_func: PrimitiveFunction):
-        if name in self._functions:
+        if name in self.functions:
             raise ValueError(f"function already registered with name '{name}'")
-        self._functions[name] = wrapped_func
+        self.functions[name] = wrapped_func
 
     def set_client(self, client: Client):
-        """Set the Client instance used to dispatch calls to local functions."""
-        self._client = client
-        for fn in self._functions.values():
+        """Set the Client instance used to dispatch calls to registered functions."""
+        self.client = client
+        for fn in self.functions.values():
             fn._client = client
 
 
diff --git a/tests/dispatch/test_function.py b/tests/dispatch/test_function.py
index 6f4a93ab..0befc0f7 100644
--- a/tests/dispatch/test_function.py
+++ b/tests/dispatch/test_function.py
@@ -6,8 +6,11 @@
 
 class TestFunction(unittest.TestCase):
     def setUp(self):
-        self.client = Client(api_url="http://dispatch.com", api_key="foobar")
-        self.dispatch = Registry(endpoint="http://example.com", client=self.client)
+        self.dispatch = Registry(
+            endpoint="http://example.com",
+            api_url="http://dispatch.com",
+            api_key="foobar",
+        )
 
     def test_serializable(self):
         @self.dispatch.function