import type { TTSHandler, TTSOptions, TTSResult, TTSVoice } from "../../types/index.js";
/** Buffered synthesis; NeuroLink's processor handles sentence streaming. */
export declare class SixtyDBTTS implements TTSHandler {
    readonly maxTextLength = 5000;
    private readonly apiKey;
    private voices?;
    private readonly baseUrl;
    /**
     * Explicit endpoint supports deployments using their own API proxy.
     * HTTP is accepted only for a loopback host (offline tests dial
     * http://127.0.0.1:<port>); every other override must be HTTPS, since
     * requests carry `Authorization: Bearer <key>` (CodeRabbit finding on
     * the PR this was taken over from, applied here). The loopback list
     * matches proxyReplay.ts's own HTTPS-except-loopback check, including
     * "localhost" for a deployer's local proxy, not just the IP forms.
     */
    constructor(apiKey?: string, baseUrl?: string);
    isConfigured(): boolean;
    private requireKey;
    private request;
    synthesize(text: string, options?: TTSOptions): Promise<TTSResult>;
    getVoices(languageCode?: string): Promise<TTSVoice[]>;
}