When dealing with Angular 18 and Reactive Forms, it can be disconcerting to encounter the "Property 'builder' is used before initialization" problem. Inappropriate FormBuilder initialization in the constructor is usually the cause of this problem, which impacts the creation and validation of forms. The issue is frequently fixed by shifting the setup to the ngOnInit() method, which guarantees that dependencies are loaded properly. recognizing important Angular directives, such as Validators.Error-handling structures and compose() offer a solid basis for developing dynamic, intuitive forms. This article explains how to prevent and troubleshoot initialization issues in a realistic way.