import type { AxiosRequestConfig, CreateAxiosDefaults } from 'axios';
import type { Agent } from 'node:http';
/**
 * Returns the proxy URL that applies to `targetUrl` based on the standard proxy
 * environment variables (`HTTP_PROXY`, `HTTPS_PROXY`, `ALL_PROXY`, `NO_PROXY`,
 * and their lowercase variants), or `undefined` when the connection should be
 * made directly.
 */
export declare function getProxyUrl(targetUrl: string): string | undefined;
/**
 * Returns a proxy agent for connecting to `targetUrl` based on the standard
 * proxy environment variables (`HTTP_PROXY`, `HTTPS_PROXY`, `ALL_PROXY`,
 * `NO_PROXY`, and their lowercase variants), or `undefined` when no proxy
 * applies and the connection should be made directly.
 *
 * `http(s)://` proxies are tunneled via the agent matching the target's scheme;
 * `socks://`, `socks4://`, and `socks5://` proxies use the SOCKS agent (which
 * handles both HTTP and HTTPS targets).
 */
export declare function createProxyAgent(targetUrl: string): Agent | undefined;
/**
 * Installs a proxy agent on an axios config for requests to `targetUrl` and
 * disables axios's own proxy handling.
 *
 * `proxy: false` is mandatory: without it, axios re-reads the proxy environment
 * variables itself and rewrites the request, appending the proxy's port to
 * portless target URLs (e.g. `https://api.checklyhq.com` becomes
 * `https://api.checklyhq.com:8080`). Letting the agent own all proxy behavior
 * keeps the target URL intact. When no proxy applies the agent is omitted and
 * the request connects directly.
 */
export declare function assignProxy<T extends CreateAxiosDefaults | AxiosRequestConfig>(targetUrl: string, axiosConfig: T): T;