Toasts are transient, dismissible notifications. The BsToastService.pushToast(template, context) call queues a toast defined by an <ng-template>; the template receives isVisible and toastIndex from the toast container plus any properties from the context object. Inside, compose <bs-toast> with <bs-toast-header> and <bs-toast-body>, and dismiss with <bs-close [index]="index">.