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Canonical URL Declarations — Prior Text-Set Comparison
x402
Canonical URL Declarations — Prior Text-Set Comparison is a paid API for AI agents from market.datapackvibe.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-13).
Parses a web page's canonical URL link element and compares its text or attribute value against a set of previously known strings to detect changes.
Price / call$0.01
Success—
StatusUnknown
How this service works
Canonical URL declarations — Prior text-set comparison: Prior text-set comparison 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 prior text-set comparison result.
Output
Returns a bounded comparison result indicating whether the canonical URL element's extracted text or attribute value matches, partially matches, or differs from the provided set of previously known strings, along with the extracted current value.
Example use cases
SEO canonical URL drift detection
“Check if the canonical URL on https://shop.example.com/running-shoes has changed from what we saw last week — our previous values were ['https://shop.example.com/running-shoes', 'https://shop.example.com/shoes/running'] and I want to compare against the href attribute of the element with id 'main-canonical'.”
CMS migration canonical validation
“I just migrated our blog and I need to verify the canonical tags are still correct — parse https://blog.example.com/post-123 and compare its canonical href against these old CMS values: ['https://old-blog.example.com/post-123', 'https://blog.example.com/post-123'] to see if anything changed.”
Third-party HTML audit for canonicals
“Here's the raw HTML of a page we received from a vendor: <!doctype html><html><head><link rel='canonical' href='https://vendor.com/item/99' id='can'></head><body></body></html> — compare the canonical href on element id 'can' against our known previous values ['https://vendor.com/item/99', 'https://vendor.com/product/99'] and tell me if it matches.”
Technical details
Endpoint
POSThttps://market.datapackvibe.com/x402/assistant-bx-web-canonical-compare?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a lightweight, low-cost static parse of a page's canonical URL declaration and want to compare it against a known set of prior values to detect drift or confirm stability. Ideal for SEO monitoring pipelines, CMS migration audits, and agentic workflows that need to track canonical URL changes over time without requiring JavaScript rendering or login access.
Side effects
- URL is inaccessible or returns non-200 status — parsing fails with an error
- HTML does not contain a canonical link element — empty or null result returned
- JavaScript-rendered canonical tags are not detected — static parsing only, no JS execution
- Attribute or attribute_value selector finds no matching element — comparison cannot proceed
- HTML input exceeds 100,000 character limit — request rejected
- previous_texts array exceeds 200 items — request rejected
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| url | string | |
| html | string | |
| term | string | |
| attribute | string | |
| previous_texts | array | |
| attribute_value | string |
Tags
x402
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