diff --git a/stdlib/2.7/json.pyi b/stdlib/2.7/json.pyi
index 77720eb54..f31937109 100644
--- a/stdlib/2.7/json.pyi
+++ b/stdlib/2.7/json.pyi
@@ -1,4 +1,4 @@
-from typing import Any, IO
+from typing import Any, IO, Optional, Tuple, Callable, Dict, List
 
 class JSONDecodeError(object):
     def dumps(self, obj: Any) -> str: ...
@@ -6,7 +6,49 @@ class JSONDecodeError(object):
     def loads(self, s: str) -> Any: ...
     def load(self, fp: IO[str]) -> Any: ...
 
-def dumps(obj: Any, sort_keys: bool = ..., indent: int = ...) -> str: ...
-def dump(obj: Any, fp: IO[str], *args: Any, **kwds: Any) -> None: ...
-def loads(s: str) -> Any: ...
-def load(fp: IO[str]) -> Any: ...
+def dumps(obj: Any,
+    skipkeys: bool = ...,
+    ensure_ascii: bool = ...,
+    check_circular: bool = ...,
+    allow_nan: bool = ...,
+    cls: Any = ...,
+    indent: Optional[int] = ...,
+    separators: Optional[Tuple[str, str]] = ...,
+    encoding: str = ...,
+    default: Optional[Callable[[Any], Any]] = ...,
+    sort_keys: bool = ...,
+    **kwds: Any) -> str: ...
+
+def dump(obj: Any,
+    fp: IO[str],
+    skipkeys: bool = ...,
+    ensure_ascii: bool = ...,
+    check_circular: bool = ...,
+    allow_nan: bool = ...,
+    cls: Any = ...,
+    indent: Optional[int] = ...,
+    separators: Optional[Tuple[str, str]] = ...,
+    encoding: str = ...,
+    default: Optional[Callable[[Any], Any]] = ...,
+    sort_keys: bool = ...,
+    **kwds: Any) -> None: ...
+
+def loads(s: str,
+    encoding: Any = ...,
+    cls: Any = ...,
+    object_hook: Callable[[Dict], Any] = ...,
+    parse_float: Optional[Callable[[str], Any]] = ...,
+    parse_int: Optional[Callable[[str], Any]] = ...,
+    parse_constant: Optional[Callable[[str], Any]] = ...,
+    object_pairs_hook: Optional[Callable[[List[Tuple[Any, Any]]], Any]] = ...,
+    **kwds: Any) -> Any: ...
+
+def load(fp: IO[str],
+    encoding: Optional[str] = ...,
+    cls: Any = ...,
+    object_hook: Callable[[Dict], Any] = ...,
+    parse_float: Optional[Callable[[str], Any]] = ...,
+    parse_int: Optional[Callable[[str], Any]] = ...,
+    parse_constant: Optional[Callable[[str], Any]] = ...,
+    object_pairs_hook: Optional[Callable[[List[Tuple[Any, Any]]], Any]] = ...,
+    **kwds: Any) -> Any: ...
diff --git a/stdlib/3/json.pyi b/stdlib/3/json.pyi
index 348f4af08..aec903f55 100644
--- a/stdlib/3/json.pyi
+++ b/stdlib/3/json.pyi
@@ -1,4 +1,4 @@
-from typing import Any, IO
+from typing import Any, IO, Optional, Tuple, Callable, Dict, List
 
 class JSONDecodeError(object):
     def dumps(self, obj: Any) -> str: ...
@@ -6,7 +6,46 @@ class JSONDecodeError(object):
     def loads(self, s: str) -> Any: ...
     def load(self, fp: IO[str]) -> Any: ...
 
-def dumps(obj: Any) -> str: ...
-def dump(obj: Any, fp: IO[str], *args: Any, **kwds: Any) -> None: ...
-def loads(s: str) -> Any: ...
-def load(fp: IO[str]) -> Any: ...
+def dumps(obj: Any,
+    skipkeys: bool = ...,
+    ensure_ascii: bool = ...,
+    check_circular: bool = ...,
+    allow_nan: bool = ...,
+    cls: Any = ...,
+    indent: Optional[int] = ...,
+    separators: Optional[Tuple[str, str]] = ...,
+    default: Optional[Callable[[Any], Any]] = ...,
+    sort_keys: bool = ...,
+    **kwds: Any) -> str: ...
+
+def dump(obj: Any,
+    fp: IO[str],
+    skipkeys: bool = ...,
+    ensure_ascii: bool = ...,
+    check_circular: bool = ...,
+    allow_nan: bool = ...,
+    cls: Any = ...,
+    indent: Optional[int] = ...,
+    separators: Optional[Tuple[str, str]] = ...,
+    default: Optional[Callable[[Any], Any]] = ...,
+    sort_keys: bool = ...,
+    **kwds: Any) -> None: ...
+
+def loads(s: str,
+    encoding: Any = ..., # ignored and deprecated
+    cls: Any = ...,
+    object_hook: Callable[[Dict], Any] = ...,
+    parse_float: Optional[Callable[[str], Any]] = ...,
+    parse_int: Optional[Callable[[str], Any]] = ...,
+    parse_constant: Optional[Callable[[str], Any]] = ...,
+    object_pairs_hook: Optional[Callable[[List[Tuple[Any, Any]]], Any]] = ...,
+    **kwds: Any) -> Any: ...
+
+def load(fp: IO[str],
+    cls: Any = ...,
+    object_hook: Callable[[Dict], Any] = ...,
+    parse_float: Optional[Callable[[str], Any]] = ...,
+    parse_int: Optional[Callable[[str], Any]] = ...,
+    parse_constant: Optional[Callable[[str], Any]] = ...,
+    object_pairs_hook: Optional[Callable[[List[Tuple[Any, Any]]], Any]] = ...,
+    **kwds: Any) -> Any: ...