Tech stack detection

Detect the technology stack of a public website: CDN, web server, language/runtime, frontend framework (Next.js, Nuxt, SvelteKit, Remix, Astro, React, Vue, Angular), CMS (WordPress, Drupal, Ghost, Shopify, Wix, Squarespace, Webflow), analytics (GA, GTM, PostHog, Mixpanel, Segment, Hotjar, Plausible, Fathom), and payments (Stripe, PayPal). Signature-based; no third-party API.

Input

Field	Type	Description
url *	string	Public http(s) URL to fingerprint

Example output

{
  "url": "https://example.com/",
  "detected": [
    {
      "category": "server",
      "name": "nginx"
    }
  ],
  "byCategory": {
    "server": [
      "nginx"
    ]
  },
  "generator": null,
  "server": "nginx",
  "poweredBy": null,
  "fetchedAt": "2026-06-19T22:00:00.000Z"
}

Try it — see the 402 challenge (free)

curl -i -X POST https://agent402.tools/api/tech-stack \
  -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/tech-stack", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "url": "https://example.com"
  }),
});

Wallet-only. This tool reaches the network/browser/storage, so it is paid in USDC via x402 (no proof-of-work tier).

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