import { DocumentNode } from 'graphql';
/**
 * HTTP client for making GraphQL API requests
 *
 * This class handles the low-level HTTP communication with the GraphQL API,
 * including authentication, request formatting, and error handling.
 */
export declare class Client {
    private client;
    /**
     * Initialize the HTTP client
     *
     * @param apiUrl The base URL for the GraphQL API
     * @param subscriptionKey Your API subscription key
     */
    constructor(apiUrl: string, subscriptionKey: string);
    /**
     * Execute a GraphQL query
     *
     * @param query The GraphQL query to execute
     * @returns The query results from the 'data' field of the GraphQL response
     * @throws Error When:
     *               - JSON encoding/decoding fails
     *               - HTTP request fails (non-200 status)
     *               - GraphQL response contains errors
     *               - Network or other errors occur
     */
    execute<T = any>(query: string | DocumentNode): Promise<T>;
}