{"uid":"cap_Y2OiW_HSNgcnfK5XijDQz","slug":"kairostamp-change-check-c51a526d","name":"Kairostamp Change Check","description":"Kairostamp change check: server-side fetch of one public http/https URL, compared against a caller-supplied prior SHA-256 or prior Kairostamp receipt id. Returns whether the response body changed, both digests, and a new time-stamped evidence receipt with its tamper-evident hash-chain entry. One call performs one check; repeat monitoring means calling again.","url":"https://kairostamp.com/api/v1/change-check?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":null,"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.05","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":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_Fyzaye87vDPV4MHEGgNrG","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x036CbD53842c5426634e7929541eC2318f3dCF7e","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Fetches a public URL server-side, compares its response body against a prior SHA-256 or Kairostamp receipt, and returns whether the content changed along with a new tamper-evident timestamped evidence receipt.","exampleAgentPrompt":"Check whether https://example.com/terms-of-service has changed since I last saw it — use this prior SHA-256 as the baseline: a3f1c2e4b5d6789012345678901234567890123456789012345678901234abcd, and give me a timestamped receipt of the result.","exampleUseCases":[{"title":"Legal document change detection","prompt":"Has the privacy policy at https://acmecorp.com/privacy changed since we audited it? Here's the SHA-256 we recorded last month: d4e5f6a7b8c9012345678901234567890123456789012345678901234567890f — give me a receipt I can attach to our compliance log."},{"title":"Supplier price list drift monitoring","prompt":"Check if the public price list at https://supplier.example.com/prices.json has changed from the snapshot we captured yesterday — the prior receipt ID is 3fa85f64-5717-4562-b3fc-2c963f66afa6. I need to know if anything shifted."},{"title":"Regulatory filing verification","prompt":"Verify whether the SEC filing page at https://sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0001234567 still matches the hash we recorded: 9b2e1f3a4c5d678901234567890123456789012345678901234567890123bcde, and produce a tamper-evident receipt as evidence."}],"resultDescription":"Returns a JSON object indicating whether the response body changed (boolean), the current SHA-256 digest of the fetched page, the prior SHA-256 digest used for comparison, a new Kairostamp evidence receipt with a UUID receipt ID, a timestamp, and a tamper-evident hash-chain entry linking this check to the prior receipt or hash.","failureModes":["URL is not publicly reachable or returns an error status — check fails with a fetch error","URL uses a non-http/https scheme — rejected as invalid input","Neither prior_sha256 nor prior_receipt_id supplied — request rejected","Both prior_sha256 and prior_receipt_id supplied simultaneously — request rejected with conflict error","prior_receipt_id refers to an unknown or expired receipt — lookup failure","URL returns a redirect to a private or non-routable address — blocked for security","Response body too large to hash within timeout — fetch timeout error"],"whenToPreferThis":"Use this endpoint when you need both a change-detection answer and a cryptographic, tamper-evident audit trail in a single call. It is ideal for compliance monitoring, legal evidence gathering, or automated alerting workflows where you need a hash-chain receipt proving the state of a URL at a specific moment. Prefer it over simple diff tools or basic polling when tamper-evident provenance matters, or when you already have a prior Kairostamp receipt ID and want to chain evidence. For first-time snapshots with no prior baseline, use the sibling URL digest receipt endpoint first.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-11T18:33:47.760Z","isFirstParty":false,"canonicalSlug":"kairostamp-change-check-c51a526d"}