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URL Change Watch
x402
URL Change Watch is a paid API for AI agents from well-009-url-change-watch.rainmaker-wells.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-22).
Fetches a public HTTPS URL, computes SHA-256 of the response body, and reports whether the content has changed compared to a previously recorded 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
A JSON object containing: the requested URL, the final URL after redirects, content_type, byte_length, sha256 hash of the response body, optional ETag and last_modified headers, a boolean 'changed' flag indicating whether content differs from the supplied previous_sha256 or previous_etag, any warnings (e.g. redirect notices, size limits), and an optional body_preview if include_body_if_changed was set.
Example use cases
Monitor competitor pricing page
“Check if https://competitor.com/pricing has changed since my last check — I stored the SHA-256 as 9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a8b, and include the body if anything is different.”
Track government regulation updates
“Has the content at https://regulations.gov/document/some-rule changed since yesterday? My previous SHA-256 was 3fdba35f04dc8c462986c992bcf875546257113072a909c162f7e470e581e278 — let me know if anything is different.”
Verify static asset integrity
“Fetch https://cdn.myapp.com/bundle.js and tell me its current SHA-256 hash — I want to compare it to 7de9f8ba2f56e2b20d40daa5c4f7a9f3d2e6b8c1 to confirm the file hasn't been tampered with.”
Technical details
Endpoint
POSThttps://well-009-url-change-watch.rainmaker-wells.workers.dev/mcp?utm_source=zero.xyz#url-change-check#url-change-checkWhen to prefer
Use this endpoint when you need lightweight, hash-based change detection for a public HTTPS URL without setting up a persistent webhook or crawler. It is ideal for polling-based monitoring workflows where an agent periodically checks a URL and compares the current SHA-256 or ETag to a previously stored value. Prefer it over full scraping tools when you only need to know if content changed (not what changed), or when you want to verify the integrity of a static asset. Not suitable for private/internal URLs, URLs requiring authentication, or bodies larger than 1 MB.
Side effects
- Non-HTTPS URLs (http, file, data, localhost, private IPs) are rejected with an error
- Response bodies exceeding 1 MB are truncated or rejected
- Target URL takes longer than ~10 seconds to respond — timeout error
- More than 5 redirects causes a redirect-limit error
- Target server returns a non-200 status — reflected in warnings or error
- Network errors reaching the target URL
Tags
x402
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