diff --git a/gradio/external_utils.py b/gradio/external_utils.py
index 8b69721aa9..28af83474a 100644
--- a/gradio/external_utils.py
+++ b/gradio/external_utils.py
@@ -16,6 +16,7 @@
 
 from gradio import components
 from gradio.exceptions import Error, TooManyRequestsError
+from typing import Any
 
 
 def get_model_info(model_name, hf_token=None):
@@ -150,28 +151,29 @@ def chat_fn(message, history):
 
 def encode_to_base64(r: httpx.Response) -> str:
     # Handles the different ways HF API returns the prediction
-    base64_repr = base64.b64encode(r.content).decode("utf-8")
+    # Handles the different ways HF API returns the prediction
+    # Use a function-local variable for the frequently used data prefix
     data_prefix = ";base64,"
+    # Fast-path: if content-type header says json, try that branch directly to avoid wasteful base64 encoding (big win for most JSON API responses)
+    content_type = r.headers.get("content-type")
+    if content_type == "application/json":
+        try:
+            # Only decode once
+            data: Any = r.json()[0]
+            content_type = data["content-type"]
+            base64_repr = data["blob"]
+        except KeyError as ke:
+            raise ValueError(
+                "Cannot determine content type returned by external API."
+            ) from ke
+        return f"data:{content_type}{data_prefix}{base64_repr}"
+    # Otherwise: Non-JSON direct response. Do base64 encoding.
+    base64_repr = base64.b64encode(r.content).decode("utf-8")
     # Case 1: base64 representation already includes data prefix
     if data_prefix in base64_repr:
         return base64_repr
-    else:
-        content_type = r.headers.get("content-type")
-        # Case 2: the data prefix is a key in the response
-        if content_type == "application/json":
-            try:
-                data = r.json()[0]
-                content_type = data["content-type"]
-                base64_repr = data["blob"]
-            except KeyError as ke:
-                raise ValueError(
-                    "Cannot determine content type returned by external API."
-                ) from ke
-        # Case 3: the data prefix is included in the response headers
-        else:
-            pass
-        new_base64 = f"data:{content_type};base64,{base64_repr}"
-        return new_base64
+    # If not, must synthesize the prefix
+    return f"data:{content_type}{data_prefix}{base64_repr}"
 
 
 def format_ner_list(input_string: str, ner_groups: list[dict[str, str | int]]):