{"uid":"cap_TGI56v9_vtp9onIVQr7Tm","slug":"sentinel-24-hour-url-watcher-8eb3f546","name":"Sentinel 24-Hour URL Watcher","description":"Watch a URL for 24 hours: signed callbacks when its verdict changes","url":"https://sentinel.rootstuff.io/x402/watch-24h","method":"GET","headers":{},"bodySchema":{"type":"object","properties":{"url":{"type":"string","description":"The http(s) URL to watch. Public hosts only."},"payload":{"type":"object","description":"Up to 4 KB of JSON echoed back in every callback."},"callback_url":{"type":"string","description":"Public https URL that receives the POSTs. Private and reserved addresses are refused; redirects are not followed."}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.5","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.5/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.5","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.5","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_96ftcafrtwbS85pv3avr8","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.5","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Monitors a public URL for 24 hours and delivers signed webhook callbacks whenever its availability/verdict changes","exampleAgentPrompt":"Watch https://api.myservice.com/health for the next 24 hours and POST a signed callback to https://hooks.myapp.com/sentinel whenever its verdict changes — include {\"service\":\"api-health-check\"} in every callback.","exampleUseCases":[{"title":"E-commerce checkout downtime alert","prompt":"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."},{"title":"Third-party dependency health watch","prompt":"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?"},{"title":"Post-deployment site verification","prompt":"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."}],"resultDescription":"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.","failureModes":["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"],"whenToPreferThis":"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.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T18:48:39.551Z","isFirstParty":false}