Webwache Canonical Change Compare

Use this endpoint when you need a passive, read-only comparison of a public web resource against a baseline or a second URL to detect changes or evaluate a criterion. Prefer it over generic scraping tools when you need a structured verdict with evidence provenance and limitation disclosure. It is ideal for monitoring workflows where you already have a baseline snapshot and want to evaluate drift without triggering any active interaction with the target site.

• Target URL is unreachable or returns non-200 status — endpoint may return an error or limited observation
• Target requires authentication — passive fetch will fail or return login page content instead of actual content
• Target blocks crawlers via robots.txt or rate limiting — observation may be incomplete or empty
• Baseline schema mismatch — if the supplied baseline is from an incompatible snapshot version, comparison may be undefined
• Comparison URL is unavailable — verdict may fall back to single-source analysis only
• Very large pages may be truncated, affecting completeness of the evidence