import { ConfigService } from '@nestjs/config';
export declare class MailService {
    private configService;
    private readonly logger;
    private transporter;
    constructor(configService: ConfigService);
    sendInvoiceEmail(to: string, data: {
        tenantName: string;
        plan: string;
        amount: string;
        transactionId: string;
    }): Promise<boolean>;
}