export interface VonageConfig {
    /** Vonage `api_key` — sent as a form field in the POST body, not a header. */
    apiKey: string;
    /** Vonage `api_secret` — sent as a form field in the POST body, not a header. */
    apiSecret: string;
    /**
     * Default sender (E.164 or alphanumeric). Optional, so supplying `from` per call
     * is sufficient; a per-call value overrides this one.
     */
    from?: string;
    /** BYO fetch hook — the wrapper holds no state. */
    fetch?: typeof fetch;
}