diff --git a/src/ahttpx/_content.py b/src/ahttpx/_content.py
index 78fd410..e75d30f 100644
--- a/src/ahttpx/_content.py
+++ b/src/ahttpx/_content.py
@@ -18,14 +18,14 @@
 
 # https://github.com/nginx/nginx/blob/master/conf/mime.types
 _content_types = {
-    "json": "application/json",
-    "js": "application/javascript",
-    "html": "text/html",
-    "css": "text/css",
-    "png": "image/png",
-    "jpeg": "image/jpeg",
-    "jpg": "image/jpeg",
-    "gif": "image/gif",
+    ".json": "application/json",
+    ".js": "application/javascript",
+    ".html": "text/html",
+    ".css": "text/css",
+    ".png": "image/png",
+    ".jpeg": "image/jpeg",
+    ".jpg": "image/jpeg",
+    ".gif": "image/gif",
 }
 
 
diff --git a/src/httpx/_content.py b/src/httpx/_content.py
index c1ee4ad..1ee0ef2 100644
--- a/src/httpx/_content.py
+++ b/src/httpx/_content.py
@@ -18,14 +18,14 @@
 
 # https://github.com/nginx/nginx/blob/master/conf/mime.types
 _content_types = {
-    "json": "application/json",
-    "js": "application/javascript",
-    "html": "text/html",
-    "css": "text/css",
-    "png": "image/png",
-    "jpeg": "image/jpeg",
-    "jpg": "image/jpeg",
-    "gif": "image/gif",
+    ".json": "application/json",
+    ".js": "application/javascript",
+    ".html": "text/html",
+    ".css": "text/css",
+    ".png": "image/png",
+    ".jpeg": "image/jpeg",
+    ".jpg": "image/jpeg",
+    ".gif": "image/gif",
 }