type ITokenExchangeResponse = {
    success: boolean;
    token?: string;
    message?: string;
};
type IErrorResponse = {
    message?: string;
};
declare const toBase64Url: (bytes: Uint8Array) => string;
declare const generatePkceVerifier: () => string;
declare const pkceChallengeFromVerifier: (verifier: string) => Promise<string>;
declare const isErrorResponse: (data: unknown) => data is IErrorResponse;
declare const exchangeToken: (code: string, verifier: string) => Promise<ITokenExchangeResponse>;
export { exchangeToken, generatePkceVerifier, isErrorResponse, pkceChallengeFromVerifier, toBase64Url };
export type { IErrorResponse, ITokenExchangeResponse };