AI x402 API recommender: ranked, preflighted picks API

AI recommendation of the best paid x402 API for a task in plain words. Ultravioleta Bazaar and 402 Index listings are deduped and keyword-scored; Anthropic Claude reranks up to 30 for fit. The first 3 GET picks get a live unpaid preflight: valid 402, live USDC price, networks, risk flags, OFAC payTo screen, domain age. Each result: URL, description, price, networks, usage evidence, preflight, AI-written reason, verbatim-checked listing quote. Kit Rx routes are labelled.

$0.005 per call USDC over x402 v2 on Base, Polygon, Arbitrum, Avalanche or Sei. No signup, no API key. Requests that fail or match nothing are not charged.

Endpoint

GET https://api.kit-rx.com/v1/x402/recommend

Parameters

Name	Type	Required	Description
`task`	string	yes	What the agent needs done, in plain words, 3-300 characters (e.g. get a 7-day weather forecast for a US city, check if a token contract is a honeypot). e.g. `get a 7-day weather forecast for a US city`
`max_price_usd`	string	no	Highest acceptable price per call in USD as a decimal, e.g. 0.01. Listings without a USDC price are left out when set; a higher live price fails the preflight. e.g. `0.01`
`network`	string: base, polygon, arbitrum, avalanche, sei, solana	no	Only endpoints that accept canonical USDC on this network.
`limit`	integer	no	Number of recommendations, 1-5 (default 3). The first 3 checkable ones get a live preflight. e.g. `2`

Example request

https://api.kit-rx.com/v1/x402/recommend?task=get+a+7-day+weather+forecast+for+a+US+city&limit=2

Without payment the server answers 402 Payment Required with the price (5000 atomic USDC) in the PAYMENT-REQUIRED header. Any x402 v2 client pays and retries automatically. A request with no parameters runs this example.

curl -i "https://api.kit-rx.com/v1/x402/recommend?task=get+a+7-day+weather+forecast+for+a+US+city&limit=2"

Pay from an agent

AgentCash: fetch the URL. OpenDexter MCP: x402_fetch. Kit Rx MCP server: https://api.kit-rx.com/mcp. Code:

import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { wrapFetchWithPayment } from "@x402/fetch";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.BUYER_KEY) });
const pay = wrapFetchWithPayment(fetch, client);
const res = await pay("https://api.kit-rx.com/v1/x402/recommend?task=get+a+7-day+weather+forecast+for+a+US+city&limit=2");
console.log(await res.json());

Example response

{
  "query": {
    "task": "get a 7-day weather forecast for a US city",
    "limit": 2
  },
  "result": {
    "results": [
      {
        "rank": 1,
        "resource": "https://api.agentstools.dev/forecast",
        "title": "api.agentstools.dev",
        "operator": "api.agentstools.dev",
        "description": "Official US weather forecast from the National Weather Service (NOAA): multi-day and hourly periods for any US coordinates or street address. Temperature in Celsius and Fahrenheit, precipitation…",
        "method": "GET",
        "price_usd": "0.003",
        "networks": [
          "eip155:8453"
        ],
        "usage_evidence": [
          {
            "source": "Ultravioleta DAO x402 Bazaar (discovery API)",
            "source_url": "https://facilitator.ultravioletadao.xyz/discovery/resources",
            "paid_calls_30d": 0,
            "unique_payers_30d": 0,
            "health": "alive",
            "uptime_pct": 100,
            "verified_at": "2026-11-13T23:58:44.000Z"
          }
        ],
        "preflight": {
          "checked": true,
          "verdict": "pass",
          "http_status": 402,
          "latency_ms": 1119,
          "is_x402": true,
          "x402_version": 2,
          "challenge_valid": true,
          "price_usd": {
            "min": "0.003",
            "max": "0.003"
          },
          "networks": [
            "eip155:8453"
          ],
          "canonical_usdc": true,
          "ofac_sdn_match": false,
          "risk_flags": [],
          "problems": [],
          "domain": {
            "registrable": "agentstools.dev",
            "platform": null,
            "age_days": null,
            "rdap": "denied"
          }
        },
        "reason": "Delivers official NWS multi-day forecast periods for any US address or coordinates, including temperature and precipitation probability.",
        "quote_from_listing": "Official US weather forecast from the National Weather Service (NOAA): multi-day and hourly periods for any US coordinates or street address."
      },
      {
        "rank": 2,
        "resource": "https://api.kit-rx.com/v1/geo/weather",
        "title": "Kit Rx",
        "operator": "kit-rx",
        "description": "Weather forecast and active alerts for a US address or lat/lon point: NWS office, grid, forecast and county zones, time zone; 7-day periods (temperature, wind, precipitation chance, short and…",
        "method": "GET",
        "price_usd": "0.005",
        "networks": [
          "eip155:8453",
          "eip155:137",
          "eip155:42161",
          "eip155:43114",
          "eip155:1329"
        ],
        "usage_evidence": [
          {
            "source": "Ultravioleta DAO x402 Bazaar (discovery API)",
            "source_url": "https://facilitator.ultravioletadao.xyz/discovery/resources",
            "paid_calls_30d": 0,
            "unique_payers_30d": 0,
            "health": "alive",
            "uptime_pct": 100,
            "verified_at": "2026-11-14T22:21:03.000Z"
          }
        ],
        "preflight": {
          "checked": true,
          "verdict": "fail",
          "http_status": 522,
          "latency_ms": 19,
          "is_x402": false,
          "x402_version": null,
          "challenge_valid": false,
          "price_usd": null,
          "networks": [],
          "canonical_usdc": null,
          "ofac_sdn_match": null,
          "risk_flags": [],
          "problems": [
            "Answered HTTP 522, not 402, so there is no payment challenge."
          ],
          "domain": {
            "registrable": "kit-rx.com",
            "platform": null,
            "age_days": 346,
            "rdap": "found"
          }
        },
        "reason": "Provides a 7-day weather forecast with temperature, wind, and precipitation chance for a US address or lat/lon point via NWS.",
        "quote_from_listing": "7-day periods (temperature, wind, precipitation chance, short and detailed forecast)"
      }
    ],
    "counts": {
      "ultravioleta": {
        "status": "ok",
        "returned": 20
      },
      "402index": {
        "status": "ok",
        "returned": 23
      },
      "merged": 31,
      "dropped": {
        "no_keyword_match": 6,
        "over_max_price": 0,
        "network_mismatch": 0,
        "reported_down": 0
      },
      "after_filters": 25,
      "sent_to_model": 25,
      "picked": 2,
      "rejected_picks": 0,
      "live_checked": 2
    },
    "model_family": "Claude",
    "ai_generated": true
  },
  "sources": [
    {
      "name": "Ultravioleta DAO x402 Bazaar (discovery API)",
      "url": "https://facilitator.ultravioletadao.xyz/discovery/resources"
    },
    {
      "name": "402 Index public API (402index.io)",
      "url": "https://402index.io/api/v1/services"
    },
    {
      "name": "Cloudflare DNS over HTTPS (JSON API)",
      "url": "https://cloudflare-dns.com/dns-query"
    },
    {
      "name": "IANA RDAP bootstrap",
      "url": "https://data.iana.org/rdap/dns.json"
    },
    {
      "name": "Registry RDAP (rdap.verisign.com)",
      "url": "https://rdap.verisign.com/com/v1/domain/kit-rx.com"
    },
    {
      "name": "Anthropic Claude (AI-generated text)",
      "url": "https://www.anthropic.com/claude"
    },
    {
      "name": "Unpaid GET of the endpoint (no payment header)",
      "url": "https://api.kit-rx.com/v1/geo/weather"
    },
    {
      "name": "Unpaid GET of the endpoint (no payment header)",
      "url": "https://api.agentstools.dev/forecast"
    }
  ],
  "notes": [
    "Ranking and reasons are AI-generated by Anthropic Claude under a fixed Kit Rx prompt from the listings' own text; quote_from_listing is copied from the listing and checked verbatim by code. Check the listing and the preflight before paying.",
    "Listings come from the Ultravioleta DAO x402 Bazaar and 402 Index; names, descriptions, prices and usage figures are published by the endpoint operators or those directories and are not verified by Kit Rx. preflight is Kit Rx's own unpaid GET made for this query.",
    "Results with operator \"kit-rx\" are Kit Rx's own endpoints. They were scored, filtered and ranked by the same rules and prompt as every other listing, with no preference.",
    "1 pick(s) failed the live preflight and were moved below the others."
  ],
  "attribution": [
    "Listings from the Ultravioleta DAO x402 Bazaar and 402 Index (402index.io); names, descriptions and prices are published by each endpoint's operator and are not verified by Kit Rx.",
    "DNS resolved via Cloudflare 1.1.1.1 DNS-over-HTTPS.",
    "Registration data from the domain's registry via RDAP, subject to that registry's terms; provided for per-domain due diligence only, not for bulk collection or marketing."
  ],
  "generated_at": "2026-11-15T05:52:32.996Z"
}

Kit Rx: Pay-per-call data and safety tools for AI agents, paid in USDC over x402. No signup, no API key. Machine-readable: OpenAPI, llms.txt, /.well-known/x402, agent skills.