diff --git a/lib/simple_spark/client.rb b/lib/simple_spark/client.rb
index 3bf97c1..c47caa0 100644
--- a/lib/simple_spark/client.rb
+++ b/lib/simple_spark/client.rb
@@ -42,7 +42,7 @@ def call(opts)
 
       path = "#{@base_path}#{path}"
       params = { path: path, headers: headers }
-      params[:body] = body_values.to_json unless body_values.empty?
+      params[:body] = JSON.generate(body_values) unless body_values.empty?
       params[:query] = query_params unless query_params.empty?
 
       if @debug