// @ts-expect-error Optional dependency
import type * as Application from "koa";
/**
 * Calling this function will setup rate limiting and user blocking for the provided Express app.
 * Attacks will still be blocked by Zen if you do not call this function.
 * Execute this function as early as possible in your Express app, but after the middleware that sets the user.
 */
export declare function addKoaMiddleware(app: Application): void;