/**
 * Generate an HMAC signature for a given payload and timestamp.
 */
export declare function generateHmacSignature(payload: any, timestamp: number, secret: string): string;
/**
 * Validate an HMAC signature.
 */
export declare function validateHmacSignature(payload: any, signature: string, secret: string): boolean;
/**
 * Send a webhook request to the given URL with the specified data and headers.
 */
export declare function sendWebhookRequest(webhookUrl: string, payload: any, secret: string): Promise<any>;
/**
 * Send a webhook request to the given URL with the specified data and headers.
 */
export declare function sendWebhookRequestWithHandle(webhookUrl: string, payload: any, secret: string): Promise<any>;
/**
 * Handle errors during webhook requests.
 */
export declare function handleWebhookError(err: any, defaultMessage: string): void;