/** Built-in transports and their required endpoint environment variables. */
export declare const BUILTIN_NOTIFICATION_TRANSPORT_ENV: Record<string, string>;
/**
 * Parses NOTIFICATION_TRANSPORTS the same way as NotificationEventHandler.
 * Defaults to appsync-graphql when unset or empty.
 */
export declare function parseNotificationTransports(raw: string | undefined): string[];
export declare function validateBuiltinNotificationTransportEnv(config: Record<string, unknown>): void;