diff --git a/Makefile b/Makefile
index 78bb952d69a6c..c062f8adc4b49 100644
--- a/Makefile
+++ b/Makefile
@@ -92,3 +92,6 @@ check_manifest:
 	check-manifest python_modules/dagster-webserver
 	check-manifest python_modules/dagster-graphql
 	ls python_modules/libraries | xargs -n 1 -Ipkg check-manifest python_modules/libraries/pkg
+
+externals_json_schema:
+	python scripts/generate_externals_json_schema.py
diff --git a/python_modules/dagster-externals/dagster_externals/_util.py b/python_modules/dagster-externals/dagster_externals/_util.py
index d1cc877690724..88f11cccd5c10 100644
--- a/python_modules/dagster-externals/dagster_externals/_util.py
+++ b/python_modules/dagster-externals/dagster_externals/_util.py
@@ -1,5 +1,18 @@
+import collections.abc
 import json
-from typing import Any, Optional, Sequence, TypeVar
+from typing import (
+    Any,
+    Optional,
+    Sequence,
+    Type,
+    TypeVar,
+    Union,
+    cast,
+    get_args,
+    get_origin,
+)
+
+from typing_extensions import TypedDict, get_type_hints
 
 from ._protocol import ExternalExecutionContextData, ExternalExecutionExtras
 
@@ -77,3 +90,59 @@ def assert_param_json_serializable(value: T, method: str, param: str) -> T:
             f" type, got `{type(value)}`."
         )
     return value
+
+
+# ########################
+# ##### JSON SCHEMA
+# ########################
+
+
+def typed_dict_to_json_schema(typed_dict_cls: Type[TypedDict]):
+    properties = {}
+    required = []
+
+    for field, field_type in get_type_hints(typed_dict_cls).items():
+        schema = process_field_type(field_type)
+        properties[field] = schema
+        required.append(field)
+
+    return {"type": "object", "properties": properties, "required": required}
+
+
+def process_field_type(field_type: Type[Any]):
+    origin = get_origin(field_type)
+    args = get_args(field_type)
+
+    # Handle basic types
+    if field_type == int:
+        return {"type": "integer"}
+    elif field_type == float:
+        return {"type": "number"}
+    elif field_type == str:
+        return {"type": "string"}
+    elif field_type == bool:
+        return {"type": "boolean"}
+    # Handle optional types
+    elif origin is Union and len(args) == 2 and type(None) in args:
+        inner_type = args[0] if args[1] is type(None) else args[1]
+        return process_field_type(inner_type)
+    # Handle nested TypedDict
+    elif (
+        isinstance(field_type, type) and issubclass(field_type, dict) and get_type_hints(field_type)
+    ):
+        return typed_dict_to_json_schema(cast(Type[TypedDict], field_type))
+    # Handle sequences
+    # at runtime the origin will come from collections.abc instead of typing
+    elif origin is collections.abc.Sequence:
+        item_type = args[0]
+        return {"type": "array", "items": process_field_type(item_type)}
+    # Handle mappings
+    # at runtime the origin will come from collections.abc instead of typing
+    elif origin is collections.abc.Mapping:
+        key_type, value_type = args
+        if key_type != str:
+            raise ValueError(f"Unsupported key type {key_type} for Mapping")
+        additional_properties = True if value_type is Any else process_field_type(value_type)
+        return {"type": "object", "additionalProperties": additional_properties}
+    else:
+        raise ValueError(f"Unsupported type {field_type}")
diff --git a/scripts/generate_externals_json_schema.py b/scripts/generate_externals_json_schema.py
new file mode 100644
index 0000000000000..e69de29bb2d1d