K2 Server-side SmartObject execution is one after another only as for all server side rules. This can lead to very poor performance when it comes to loading a form that makes a large number of SmartObject calls. SmartObjects need to be able to be executed asynchronously and concurrently as well and this functionality urgently needs to be included in the product.

The rule configuration in the designer is implemented exactly the same way as Client-side SmartObject execution, this leads users to believe that the execution behaviour would be the same as for Client-Side execution. The documentation (https://help.k2.com/onlinehelp/k2cloud/userguide/update_10/default.htm#Create/K2Designer/Rules/ServerRules.htm?Highlight=%22one%20after%20another%22) however does state that rules are executed one after another server side.