{"uid":"cap_pqyFcgpE-Y3adq9eChfoF","slug":"website-change-comparison-api-8ed85f33","name":"Website Change Comparison API","description":"Evidence-backed npm package upgrade decisions for coding agents.","url":"https://x402-safe-upgrade-api.onrender.com/v1/website-change-comparison?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"websiteUrl":{"type":"string","format":"uri"},"currentSnapshot":{"type":"string","maxLength":200000,"description":"Content supplied by the caller only; it is processed in memory and not retained."},"previousSnapshot":{"type":"string","maxLength":200000,"description":"Content supplied by the caller only; it is processed in memory and not retained."}}},"responseSchema":{"type":"json","example":{"change":{"added":[],"removed":[]}}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.02","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":"down","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.02/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_hb98cIboUDeyyHvsV4ej6","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.02","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Compares two snapshots of a webpage to identify added and removed content between versions.","exampleAgentPrompt":"Compare these two snapshots of https://npmjs.com/package/lodash and tell me what content was added or removed — here's the previous snapshot and the current one I just fetched.","exampleUseCases":[{"title":"npm package changelog detection","prompt":"I have the previous and current snapshots of the lodash npm page at https://npmjs.com/package/lodash — can you compare them and tell me exactly what was added or removed so I know if it's safe to upgrade?"},{"title":"Library docs update monitoring","prompt":"Here are two versions of the React docs page at https://react.dev/reference/react/useState — the one from last week and today's. What content changed between them?"},{"title":"Dependency release notes diff","prompt":"I grabbed a snapshot of https://github.com/expressjs/express/releases before and after their latest push. Can you compare the two and show me what was added or removed from the release notes page?"}],"resultDescription":"A JSON object with a 'change' field containing two arrays: 'added' (content present in the current snapshot but not the previous) and 'removed' (content present in the previous snapshot but not the current), enabling precise diffing of webpage content.","failureModes":["Snapshots too large — each is capped at 200,000 characters; exceeding this causes rejection","Invalid or unreachable websiteUrl — malformed URI format returns an error","Both snapshots identical — returns empty added/removed arrays with no error","Malformed snapshot content (binary or non-text) may produce unexpected diff results","Missing required fields in request body returns a validation error"],"whenToPreferThis":"Use this endpoint when you need to programmatically compare two text snapshots of a webpage and extract a structured list of what was added or removed — particularly useful for coding agents evaluating npm package upgrade safety by detecting changelog or documentation changes. Prefer this over generic diff tools when you need a clean JSON result distinguishing additions from removals in a web-content context.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-12T20:26:42.125Z","isFirstParty":false,"canonicalSlug":"website-change-comparison-api-8ed85f33"}