# Canonical URL Declarations — Structured Extraction

> Canonical URL Declarations — Structured Extraction is a paid API for AI agents from market.datapackvibe.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-16).

Extracts canonical URL declarations from a public web page or supplied HTML using static parsing, returning structured results.

## Facts

- Endpoint: POST https://market.datapackvibe.com/x402/assistant-bx-web-canonical-items?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/canonical-url-declarations-structured-extraction-588b19c2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_rDEwsYXvwDjv6gG_U-sJL

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability canonical-url-declarations-structured-extraction-588b19c2 -d '<json body>'
```

Example prompt: Can you extract the canonical URL declaration from https://www.example.com/product-page — look for the element with attribute id equal to 'canonical-link' and give me the structured result?

## When to prefer this

Choose this endpoint when you need to quickly and cheaply extract canonical URL link declarations from a single public web page or a known HTML snippet using static (non-JavaScript) parsing. It is ideal for SEO audits, content deduplication checks, or structured data pipelines that need canonical tag data without full browser rendering. At $0.01 USDC per call it is cost-effective for high-volume page checks.

## Known failure modes

- URL is not publicly accessible (returns error or empty result)
- Page requires JavaScript rendering — static parsing will miss dynamically inserted canonical tags
- HTML input exceeds 100,000 character limit
- No canonical declaration found on the page (empty result returned)
- Invalid URL format provided
- Attribute pattern does not match schema regex, causing validation error

## How this service works

Canonical URL declarations — Structured extraction: Structured extraction for Canonical URL declarations. One public HTTPS page or supplied HTML; static parsing, no JavaScript rendering, login or access bypass. Specialised preset in a shared 50-profile, 20-operation engine. 0.01 USDC includes one bounded structured extraction result.

## Output

Returns a structured extraction result containing the canonical URL declaration(s) found in the page or HTML, including matched element details such as the href value, attribute matches, and surrounding context. One bounded result per call.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "default": "",
   "maxLength": 2048
  },
  "html": {
   "type": "string",
   "default": "<!doctype html><html><head></head><body><link rel=\"canonical\" href=\"https://www.iana.org/help/example-domains\" id=\"sample\"></body></html>",
   "maxLength": 100000
  },
  "term": {
   "type": "string",
   "default": "product",
   "maxLength": 100,
   "minLength": 1
  },
  "attribute": {
   "type": "string",
   "default": "id",
   "pattern": "^[a-zA-Z][a-zA-Z0-9:_-]{0,49}$",
   "maxLength": 50
  },
  "previous_texts": {
   "type": "array",
   "items": {
    "type": "string",
    "default": "",
    "maxLength": 1000
   },
   "default": [
    "Older example"
   ],
   "maxItems": 200,
   "minItems": 0
  },
  "attribute_value": {
   "type": "string",
   "default": "sample",
   "maxLength": 200
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/canonical-url-declarations-structured-extraction-588b19c2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from market.datapackvibe.com](https://www.zero.xyz/host/market.datapackvibe.com/llms.txt)