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AgentShelf CSS Canonical Link Extractor
x402
AgentShelf CSS Canonical Link Extractor is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-01).
Extracts canonical URL(s) from a public webpage or raw HTML by selecting link[rel='canonical'] elements, with SSRF protection.
Price / call$0.001
Success—
StatusUnknown
How this service works
Call when an agent needs canonical hrefs via link[rel='canonical'] from a public page or HTML (SSRF-safe). Exact $0.001 USDC. Prefer unpaid POST /v1/sandbox/css-link-canonical first.
Output
Returns the href value(s) found in link[rel='canonical'] elements from the fetched or provided HTML. Typically a single canonical URL string, or an empty result if no canonical tag is present.
Example use cases
SEO canonical tag audit
“Check https://www.myblog.com/post/how-to-bake-bread and tell me what canonical URL it declares — I want to make sure it's pointing to itself and not some other page.”
Deduplication before indexing
“Before I index this page, can you pull the canonical href from https://shop.example.com/product/blue-widget so I know which URL to store as the authoritative version?”
Canonical check from raw HTML
“I have the raw HTML of a page already — can you extract the canonical link tag href from it for me? Here it is: <html><head><link rel='canonical' href='https://example.com/real-page'/></head></html>”
Technical details
Endpoint
POSThttps://agentshelf.syntexa.ch/v1/css-link-canonical?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to programmatically determine the canonical URL of a page for SEO auditing, deduplication, or crawl prioritization. Prefer the free sandbox endpoint (/v1/sandbox/css-link-canonical) for testing. Use this paid endpoint for production use where SSRF safety and reliable parsing are required. Choose this over a generic HTML fetcher when you specifically need the canonical link tag and want a clean, structured result without post-processing raw HTML yourself.
Side effects
- URL is unreachable or returns non-200 status — extraction fails with an error
- SSRF-blocked URL (private IP, metadata endpoint) — rejected before fetch
- No link[rel='canonical'] element found — returns empty result
- HTML is malformed and canonical tag is unparseable — returns empty or partial result
- Input HTML exceeds 200,000 character limit — request rejected
- URL shorter than 8 characters or longer than 2048 — validation error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| url | string | Public page to fetch. The selector or profile is fixed by the SKU. Provide url or html. |
| html | string | HTML to extract from locally. Provide html or url. When both are set, html is used. |
Tags
x402
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