/**
 * Rate Limiting Middleware
 * Prevents API abuse by limiting requests per identity.
 * Uses authenticated keyId when available, otherwise request IP.
 *
 * Two backends are supported:
 *   - memory (default): in-process Map. Resets on restart; not shared across instances.
 *   - db: Postgres-backed via iranti_rate_limits table. Shared across all instances,
 *         survives restarts. Activate with IRANTI_RATE_LIMIT_BACKEND=db.
 */
import { NextFunction, Request, Response } from 'express';
interface CheckResult {
    allowed: boolean;
    remaining: number;
    resetAt: number;
}
interface RateLimiterBackend {
    check(identity: string): CheckResult | Promise<CheckResult>;
    readonly limit: number;
}
export declare const rateLimiter: RateLimiterBackend;
export declare function rateLimitMiddleware(req: Request, res: Response, next: NextFunction): void;
export {};
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