diff --git a/src/mergerfs_webui.cpp b/src/mergerfs_webui.cpp
index 78473d96..541c1016 100644
--- a/src/mergerfs_webui.cpp
+++ b/src/mergerfs_webui.cpp
@@ -347,10 +347,10 @@ _post_kvs_key(const httplib::Request &req_,
       std::string key;
       std::string val;
 
+      j = json::parse(req_.body);
       key = req_.path_params.at("key");
       val = j;
       mount = req_.get_param_value("mount");
-      j = json::parse(req_.body);
 
       rv = mergerfs::api::set_kv(mount,key,val);