HTML links

Enumerate every <a href> in an HTML string with its anchor text and rel attribute. Optionally resolves relative hrefs against a base URL and filters by a regex on the href. The deterministic way to crawl a page's outlinks without writing a regex.

Input

Field	Type	Description
html *	string	Raw HTML string to scan (max 5MB)
base	string	Optional base URL to resolve relative hrefs against
filter	string	Optional regex applied to the href - only matching links are returned
limit	number	Max links to return, 1-1000 (default 200)
unique	boolean	Deduplicate by href (default true)

Example output

{
  "count": 2,
  "links": [
    {
      "href": "https://agent402.tools/about",
      "text": "About",
      "rel": ""
    },
    {
      "href": "https://example.com/",
      "text": "External",
      "rel": ""
    }
  ]
}

Try it - see the 402 challenge (free)

curl -i -X POST https://agent402.tools/api/html-links \
  -H "Content-Type: application/json" \
  -d '{"html":"<a href=\"/about\">About</a><a href=\"https://example.com\">External</a>","base":"https://agent402.tools"}'

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/html-links", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "html": "<a href=\"/about\">About</a><a href=\"https://example.com\">External</a>",
    "base": "https://agent402.tools"
  }),
});

No wallet? Pay with compute

This is a pure-CPU tool, so an agent without a wallet can pay with proof-of-work instead of USDC: fetch a challenge, solve the sha256 puzzle (16 leading zero bits - a fraction of a second of CPU, no money, no AI tokens), and resend with the X-Pow-Solution header.

import { createHash } from "node:crypto";
const lz = (b) => { let t = 0; for (const x of b) { if (!x) { t += 8; continue; } t += Math.clz32(x) - 24; break; } return t; };
const c = await (await fetch("https://agent402.tools/api/pow/challenge?slug=html-links")).json();
let n = 0;
while (lz(createHash("sha256").update(c.challenge + ":" + n).digest()) < c.difficulty) n++;
await fetch("https://agent402.tools/api/html-links", { method: "POST", headers: { "X-Pow-Solution": c.token + ":" + n, "Content-Type": "application/json" }, body: JSON.stringify({"html":"AboutExternal","base":"https://agent402.tools"}) });

Part of these workflows

This tool is one step in 3 curated multi-tool workflows - agents can fetch the whole sequence as an MCP prompt or call https://agent402.tools/api/skill-packs/{slug}/prompt.

• Structured scrape - Pull structured data out of any web page deterministically - articles to clean text, tables to JSON rows, specific elements via CSS selector - without writing regex against raw HTML.
• 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.
• WCAG accessibility audit - Run a deterministic WCAG 2.x audit of an HTML page from a string and a fg/bg color pair. Checks language attribute (3.1.1), document title (2.4.2), heading order (1.3.1), link-text presence (2.4.4), color contrast (1.4.3), and reading grade level (3.1.5 AAA). Seven pure-CPU tools, no headless browser needed - the canonical accessibility-first-pass workflow done as a single round-trip of tool calls.

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