diff --git a/src/main/java/im/rosetta/api/FilesResource.java b/src/main/java/im/rosetta/api/FilesResource.java
index 6141f25..90ba7bc 100644
--- a/src/main/java/im/rosetta/api/FilesResource.java
+++ b/src/main/java/im/rosetta/api/FilesResource.java
@@ -34,6 +34,7 @@ public class FilesResource {
         File target = resolved.toFile();
         return Response.ok(target)
                 .header("Content-Disposition", "attachment; filename=\"" + target.getName() + "\"")
+                .header("Content-Length", target.length())
                 .build();
     }
 
@@ -50,6 +51,7 @@ public class FilesResource {
         File target = resolved.toFile();
         return Response.ok(target)
                 .header("Content-Disposition", "attachment; filename=\"" + target.getName() + "\"")
+                .header("Content-Length", target.length())
                 .build();
     }
 }