/**
 * Isomorphic base64url encoding/decoding utilities
 * Works in both browser and Node.js environments
 */
/**
 * Encode data to base64url format
 * @param data - String, Uint8Array, or ArrayLike data to encode
 * @returns base64url encoded string
 */
declare function base64urlEncode(data: string | Uint8Array | ArrayLike<number>): string;
/**
 * Decode base64url string to Uint8Array
 * @param str - base64url encoded string
 * @returns decoded Uint8Array
 */
declare function base64urlDecode(str: string): Uint8Array;
/**
 * Decode base64url string to UTF-8 string
 * @param str - base64url encoded string
 * @returns decoded UTF-8 string
 */
declare function base64urlDecodeToString(str: string): string;
/**
 * Encode UTF-8 string to base64url format
 * @param str - UTF-8 string to encode
 * @returns base64url encoded string
 */
declare function stringToBase64url(str: string): string;

export { base64urlDecode, base64urlDecodeToString, base64urlEncode, stringToBase64url };