HTTP check

Check any public URL: status code, latency, final URL after redirects, and response headers. The uptime primitive for agent monitors.

Input

Example output

{
  "up": true,
  "status": 200,
  "latencyMs": 87,
  "finalUrl": "https://example.com/",
  "headers": {
    "content-type": "text/html"
  }
}

Try it - see the 402 challenge (free)

curl -i -X POST https://agent402.tools/api/http-check \
  -H "Content-Type: application/json" \
  -d '{"url":"https://example.com"}'

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

Paid call (JavaScript agent)

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

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/http-check", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "url": "https://example.com"
  }),
});

Part of these workflows

This tool is one step in 6 curated multi-tool workflows - agents can fetch the whole sequence as an MCP prompt or call https://agent402.tools/api/skill-packs/{slug}/prompt.

• DNS & network ops - End-to-end DNS health check: records, multi-resolver propagation, WHOIS, ASN, robots.txt, and reachability.
• API investigation - Point at an unknown API endpoint and figure out how to use it: auth scheme, content type, version, rate limits, OpenAPI/Swagger spec discovery, and JSON response structure. The deterministic recon workflow before writing a single line of integration code.
• Site status snapshot - The 'is this site healthy, addressable, and crawlable - right now?' workflow. DNS resolution → HTTP reachability → security headers → TLS certificate expiry → robots policy. Five tools, one structured status payload an operator (or an uptime bot, or a pre-flight check before an extract/crawl) can act on.
• Technical SEO audit - Can search engines and AI crawlers actually index this page? One pass over reachability, TLS, robots policy, sitemap health, meta/OpenGraph tags, and the on-page link graph.
• URL inspector - Quick URL health and metadata check - parse the URL structure, verify reachability, and pull page metadata in one pass.
• API health check - Is this API endpoint healthy? Liveness check, response headers, and TLS certificate status in one pass.

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