diff --git a/lib/api/api.rb b/lib/api/api.rb
index 283f7642f67..9022cf7375a 100644
--- a/lib/api/api.rb
+++ b/lib/api/api.rb
@@ -22,6 +22,8 @@ module API
     end
 
     format :json
+    content_type :txt, "text/plain"
+
     helpers APIHelpers
 
     mount Groups
diff --git a/lib/api/repositories.rb b/lib/api/repositories.rb
index cad64760abb..c305c889fc2 100644
--- a/lib/api/repositories.rb
+++ b/lib/api/repositories.rb
@@ -167,9 +167,7 @@ module API
         blob = Gitlab::Git::Blob.find(repo, commit.id, params[:filepath])
         not_found! "File" unless blob
 
-        env['api.format'] = :txt
-
-        content_type blob.mime_type
+        content_type 'text/plain'
         present blob.data
       end