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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 SHA-256 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? }. Provided as is, with no warranty or guarantee of accuracy or fitness. Nothing is stored.
Output
Returns a JSON object with the fetched URL, final URL after redirects, content type, byte length, computed SHA-256, optional ETag and Last-Modified headers, a boolean 'changed' field (null if baseline, true/false if compared), any warnings, and an optional truncated body preview (~8KB) if requested and content changed.
Example use cases
Monitor competitor pricing page
“Check if https://competitor.com/pricing has changed since yesterday — the previous SHA-256 was 9f86d08188f... — and show me a preview of the body if anything is different.”
Verify a published dataset hasn't changed
“I need to confirm that https://data.gov/dataset/file.csv hasn't been modified — its SHA-256 was b94f6f125c79... last time I checked. Tell me if it's still the same.”
Baseline a new URL for future monitoring
“Fetch https://status.myservice.com/api/health and give me its current SHA-256 hash so I can use it as a baseline to detect changes in the future.”
Technical details
Endpoint
POSThttps://well-009-url-change-watch.rainmaker-wells.workers.dev/api/url-change-check?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a lightweight, stateless way to check if a public HTTPS URL's content has changed based on SHA-256 hashing or ETag comparison, without maintaining your own infrastructure. It is ideal for one-off change checks, baselining a URL for future comparison, or integrating change detection into an agent workflow where storing hashes client-side is acceptable. Prefer alternatives if you need persistent server-side scheduling, monitoring many URLs continuously, or require HTTP (non-HTTPS) support.
Side effects
- Non-HTTPS URLs (http, file, data, localhost, private IPs) are rejected with an error
- Response body exceeds 1 MB cap — endpoint returns error or truncated result
- Target URL times out after ~10 seconds — returns timeout error
- More than 5 redirects encountered — returns redirect limit error
- Invalid or malformed previous_sha256 value — may produce unexpected changed result
- Target server returns non-2xx status — result may reflect error page content rather than expected resource
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| urlrequired | string | https URL to watch. http/file/data/localhost/private IPs rejected. |
| previous_etag | string | Prior ETag; used when previous_sha256 is absent and response has ETag (quotes normalized). |
| previous_sha256 | string | Hex SHA-256 of last seen body. If omitted (and no previous_etag match), this call is a baseline (changed=null). |
| include_body_if_changed | boolean | If true and changed (or baseline), include truncated body text (~8KB) as body_preview. Default false. |
Output
Schema · Response
{
"type": "object",
"additionalProperties": true
}Tags
x402
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