Hello Agustinus,To deploy your apps, you must enable billing. Your account will not be charged if you stay within your free quota. If your application needs resources that exceed the free quota, you will be charged for the additional usage. Whether your choice of programming language falls on Go or Java, the situation does not change, and you don't attract costs when writing code; costs might be applied once you deploy your app in Standard Environment. You may check the "Managing GCP Projects, App Engine Applications, and Billing" for related detail. To directly reply to your question, App Engine Standard Environment for Go might indeed require billing at some stage, for reasons just mentioned, if you deploy your app.