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Sentinel 24-Hour URL Watcher
x402
Sentinel 24-Hour URL Watcher is a paid API for AI agents from sentinel.rootstuff.io, paid per call via x402, $0.5/call, status unknown (last checked 2026-09-15).
Monitors a public URL for 24 hours and delivers signed webhook callbacks whenever its availability/verdict changes
Price / call$0.5
Success—
StatusUnknown
How this service works
Watch a URL for 24 hours: signed callbacks when its verdict changes
Output
The endpoint registers the watch job and returns a confirmation. Over the next 24 hours, whenever the monitored URL's verdict (up/down/availability status) changes, Sentinel POSTs a signed callback to the specified callback_url. Each callback includes the verdict change details and echoes back the custom payload (up to 4 KB) provided at registration. Callbacks are cryptographically signed so recipients can verify authenticity.
Example use cases
E-commerce checkout downtime alert
“Keep an eye on https://checkout.mystore.com for the full next 24 hours and hit https://alerts.mystore.com/webhook whenever it goes down or comes back up — include {"team":"ops","priority":"high"} in each callback so my on-call system knows how to route it.”
Third-party dependency health watch
“I'm integrating a third-party payment API at https://pay.vendor.com/ping — can you monitor it for 24 hours and send signed change notifications to https://hooks.internal.io/deps whenever its availability status flips?”
Post-deployment site verification
“We just deployed a new version of our app at https://www.myapp.io — watch it for the next 24 hours and send me a signed callback at https://hooks.myapp.io/deploy-monitor if anything changes, with {"deploy_id":"v2.4.1"} echoed back each time.”
Technical details
Endpoint
GEThttps://sentinel.rootstuff.io/x402/watch-24hWhen to prefer
Choose this endpoint when you need extended 24-hour continuous monitoring of a public URL with webhook-based notifications, rather than a one-off check or short-term watch. Prefer it over the 1-hour sibling when you need longer coverage — e.g. monitoring a deployment overnight or tracking a vendor API across a full business day. Prefer it over single-point checks (ping, headers, TLS) when you care about changes over time rather than a snapshot. The signed callbacks make it suitable for automated pipelines that need tamper-evident notifications.
Side effects
- Invalid or non-public target URL — private IPs or reserved addresses rejected
- Callback URL is private, uses a reserved address range, or follows redirects — request refused
- Payload exceeds 4 KB limit — request rejected
- Target URL becomes permanently unreachable — no further callbacks sent after failure
- Callback URL is unresponsive — delivery may be retried but not guaranteed
- Malformed URL schema (non-http/https) — rejected at validation
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| url | string | The http(s) URL to watch. Public hosts only. |
| payload | object | Up to 4 KB of JSON echoed back in every callback. |
| callback_url | string | Public https URL that receives the POSTs. Private and reserved addresses are refused; redirects are not followed. |
Tags
x402
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