import { BatchResponse } from 'firebase-admin/lib/messaging/messaging-api';
interface FirebaseAdminOptions {
    projectId: string;
    privateKey: string;
    clientEmail: string;
    databaseURL: string;
}
export declare class FirebaseAdmin {
    private static instance?;
    private admin;
    private constructor();
    static initialize(options: FirebaseAdminOptions): void;
    static getInstance(): FirebaseAdmin;
    sendMulticastMessaging(tokens: string[], title: string, body: string, data?: Record<string, string>): Promise<BatchResponse>;
}
export {};