import { X402Metadata, X402Requirement } from './types';
interface X402PaymentRequired {
    x402Version: number;
    accepts: X402Requirement[];
}
export declare function decodePaymentRequired(headers: Record<string, unknown> | undefined): X402PaymentRequired | undefined;
export declare function decodePaymentResponse(headers: Record<string, unknown> | undefined): Record<string, any> | undefined;
export declare function buildX402PaymentHeader(privateKey: string, paymentRequired: X402PaymentRequired): Promise<{
    encodedHeader: string;
    metadata: X402Metadata;
}>;
export declare function attachX402Metadata<T>(data: T, metadata?: X402Metadata): any;
export {};