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Webwache Canonical Change Snapshot
x402
Webwache Canonical Change Snapshot is a paid API for AI agents from webwache.halowerk.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-22).
Fetches a passive public snapshot of a target URL and evaluates a documented change criterion, returning an observation, verdict, evidence source, and limitations.
Price / call$0.001
Success—
StatusUnknown
How this service works
Canonical change snapshot fetches current public evidence from the supplied target and evaluates the documented criterion. It returns the observation, threshold, verdict, exact evidence source, limitations and a mode-specific action. The check is passive: no login attempt, payload injection, exploit, purchase, form submission or load test is performed.
Output
Returns a structured object containing: the observation (what was found on the page), a threshold or criterion evaluation, a verdict (pass/fail/uncertain), the exact evidence source URL, any limitations on the passive read, and a mode-specific recommended action. The baseline object can be stored and passed back on subsequent calls for comparison.
Example use cases
Price drop alert on product page
“Grab a snapshot of https://store.example.com/product/widget and tell me whether the listed price has dropped below $49 — I want the verdict, what you actually observed on the page, and where you found that evidence.”
Competitor homepage change detection
“Take a current snapshot of https://competitor.com and compare it against this baseline I have from last Monday — has anything meaningful changed, and what's your verdict?”
Regulatory notice monitoring
“Check https://regulator.gov/notices right now and evaluate whether a new enforcement notice has appeared on the page — give me the observation, threshold verdict, and any limitations in your read.”
Technical details
Endpoint
POSThttps://webwache.halowerk.com/v1/canonical-change-snapshot?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a passive, non-intrusive point-in-time snapshot of a public webpage to evaluate a specific observable criterion — especially when you want structured verdict output (observation + threshold + evidence source) rather than raw HTML. Prefer this over general web scrapers when you need built-in change comparison via a baseline parameter and an explicit pass/fail verdict. Not appropriate when login, form submission, or dynamic interaction with the page is required.
Side effects
- Target URL is unreachable or returns non-200 status — snapshot cannot be completed
- Target requires authentication or is behind a paywall — passive read is blocked
- Content is JavaScript-rendered and not accessible in static fetch — observation may be incomplete
- Rate limiting or bot protection on target blocks the fetch
- Baseline object is malformed or from an incompatible schema version — comparison fails
- Target domain normalizes incorrectly from bare domain input
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| target | string | Public HTTP(S) URL or domain to inspect. A bare domain is normalized to HTTPS. |
| context | object | Optional non-secret correlation labels returned unchanged only in the request lifecycle. |
| baseline | — | Optional baseline returned by a previous snapshot call. |
| compare_url | string | Optional public comparison URL. Used by change and monitoring services. |
Tags
x402
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