/**
 * Generate HMAC signature for request validation
 */
export declare function generateSignature(payload: string, secretKey: string | undefined): string;
/**
 * Check if code is running in browser environment
 */
export declare function isBrowser(): boolean;
/**
 * Check if code is running in server environment
 */
export declare function isServer(): boolean;
/**
 * Get browser information
 */
export declare function getBrowserInfo(): Record<string, any>;
/**
 * Format error object into a standardized structure
 */
export declare function formatError(error: Error | unknown): {
    name: string;
    message: string;
    stack?: string;
};
/**
 * Safe stringify function that handles circular references
 */
export declare function safeStringify(obj: any): string;
/**
 * Sanitize sensitive data from objects
 */
export declare function sanitizeData(data: Record<string, any>, sensitiveKeys?: string[]): Record<string, any>;
/**
 * Get current timestamp in ISO format
 */
export declare function getTimestamp(): string;
/**
 * Log message with prefix in debug mode
 */
export declare function debugLog(message: string, data?: any): void;