import type { EmailTransport } from './types.js';
export interface LettermintConfig {
    /** Lettermint API token, sent in the `x-lettermint-token` header. Required. */
    token: string;
    /**
     * Default sender (optionally `Display Name <addr@example.com>`), used when a
     * send carries no `from` of its own. A per-send `from` always wins. The
     * Lettermint v2 API requires a sender, so a send with neither a per-send nor a
     * configured `from` throws before issuing the request.
     */
    from?: string;
    /**
     * API base URL, without a trailing slash. The send endpoint is `${baseUrl}/send`.
     * @default 'https://api.lettermint.co/v1'
     */
    baseUrl?: string;
    /**
     * Abort the request after this many milliseconds (via `AbortSignal.timeout`),
     * surfaced as an Error so a stalled connection can't hang the caller forever.
     * @default 10000
     */
    timeoutMs?: number;
}
/**
 * Email transport backed by the Lettermint v2 send API. Zero-dependency: uses
 * the native `fetch` (no SDK). POSTs to `${baseUrl}/send` with the token in the
 * `x-lettermint-token` header and a JSON body of
 * `{ from, to: string[], subject, html?, text? }`.
 *
 * The sender resolves from the per-send `from`, falling back to the transport's
 * configured {@link LettermintConfig.from}. The API requires a sender, so a send
 * with neither throws (the auth handlers thread `config.email.from`, so their
 * mails always carry one). The request is bounded by
 * {@link LettermintConfig.timeoutMs}; a timeout and a non-2xx response are both
 * surfaced as an Error (the latter carrying the status + response body).
 */
export declare function createLettermintTransport(config: LettermintConfig): EmailTransport;