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URL Change Watch
x402
URL Change Watch is a paid API for AI agents from well-009-url-change-watch.mmelnyk2000.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-20).
Fetches a public HTTPS URL, computes a SHA-256 hash of the response body, and reports whether the content has changed compared to a previously known hash or ETag.
Price / call$0.01
Success—
StatusUnknown
How this service works
Fetch a public https URL, compute SHA-256 of the response body, and report whether it changed vs a prior sha256/etag ($0.01 USDC via x402). Sticky: store sha256 and call again later. Optional previous_sha256, previous_etag, include_body_if_changed. https only — http, file, data, localhost, and private IPs rejected. Caps: 1 MB body, ~10s timeout, max 5 redirects. Returns JSON { url, final_url, content_type, byte_length, sha256, etag?, last_modified?, changed, warnings, body_preview? }.
Output
Returns a JSON object containing the fetched URL, final URL (after redirects), content type, byte length, SHA-256 hash, optional ETag and Last-Modified header values, a boolean 'changed' flag indicating whether content differs from the prior hash/ETag, any warnings (e.g. redirect chains, large body), and an optional body preview if the content changed and was requested.
Example use cases
Monitor competitor pricing page
“Keep an eye on https://competitor.com/pricing for me — the last SHA-256 I have is e3b0c44298fc1c149afb, and let me know if anything changed, and show me the new content if it did.”
Verify static asset integrity
“Check if https://cdn.mysite.com/bundle.js has been modified since the last deploy — the previous hash was 9f86d081884c7d659a2f, so I can tell if the CDN is serving a stale version.”
Poll a public API for new data
“Has https://api.opendata.gov/records/latest.json changed since the previous ETag was "abc-etag-789"? Let me know if there's new data and show me a preview of the body.”
Technical details
Endpoint
POSThttps://well-009-url-change-watch.mmelnyk2000.workers.dev/mcp?utm_source=zero.xyz#url-change-check#url-change-checkWhen to prefer
Choose this endpoint when you need a lightweight, on-demand check of whether a specific public HTTPS URL's content has changed, especially when you already have a prior SHA-256 hash or ETag to compare against. It is ideal for polling workflows, change detection pipelines, and integrity verification of static assets or public API responses. Prefer it over full web scrapers when you only need a change signal (and optionally the body), not structured extraction.
Side effects
- Non-HTTPS URLs (http, file, data, localhost, private IPs) are rejected with an error
- Response body exceeds 1 MB limit — truncated or rejected
- Target URL times out after ~10 seconds
- More than 5 redirects — request aborted
- Target server returns non-200 status — reported with appropriate error
- Invalid or malformed URL input — validation error returned
Tags
x402
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