Website Change Diff Monitor

Monitor public webpages for meaningful changes in title, headings, body sections, CTAs, links, schema, scripts, screenshots, and key selectors between snapshots.

What it does

Compares baseline and current public-page snapshots across titles, headings, body text, CTAs, links, schema, scripts, and watched selectors.

The actor emits one row per normalized change, or an honest baseline/no-change diagnostic. Dataset and report output is produced only after every applicable PPE charge is accepted.

Common uses

• Monitor website page changes
• Track competitor homepage updates
• Detect CTA and offer changes
• Compare launch snapshots
• Export web change alerts

Input

Supply public HTTP(S) URLs or deterministic htmlInputs. URL fetching rejects localhost and private-network destinations; allowedDomains can narrow access further.

• startUrls
• sitemapUrls
• htmlInputs
• allowedDomains
• maxPages
• maxDepth
• includeEvidence
• includeRawSnapshots
• requestDelayMs
• timeoutMs
• userAgentMode
• watchUrls
• baselineSnapshots
• fetchCurrent
• changeRules
• selectorWatchlist
• ignorePatterns
• includeScreenshots
• maxTargets
• maxSnapshots
• maxChanges
• maxChargeUsd
• includeReport

The caps in maxTargets, maxPages, maxSnapshots, maxChanges, timeoutMs and maxChargeUsd are enforced. A zero charge cap is a hard zero budget.

Output

• sourceUrl
• sourceType
• pageTitle
• recordType
• recordName
• issueCode
• severity
• evidenceSnippet
• recommendation
• canonicalUrl
• httpStatus
• scannedAt
• watchUrl
• changeType
• selector
• oldValue
• newValue
• changeMagnitude
• ignoredByRule
• screenshotKey
• diffSnippet
• alertPriority

Reports:

• website-change-diff-monitor-summary-report.md
• website-change-diff-monitor-records.csv
• website-change-diff-monitor-issues.json
• website-change-diff-monitor-evidence-samples.json
• website-change-diff-monitor-run-metadata.json

Pricing

Platform-usage pass-through is off. Locked fixed-inclusive events:

Event	Price
actor-start	$0.035
target-checked	$0.0115
snapshot-compared	$0.0115
change-detected	$0.0225
digest-generated	$0.09
executive-report-generated	$0.18

The actor charges actor-start before fetching/rendering, deduplicates page events, charges record/finding events only for corresponding output, and stops before further output on partial, limited, or over-budget charges. Screenshot events fire only when a real browser PNG exists.

Safety and limitations

• Public pages only; no authentication, CAPTCHA bypass, access-control evasion, or private data.
• Browser waits, pages, records, changes, forms, popups, and screenshots are bounded.
• Blocked, empty, and missing-baseline cases produce diagnostics instead of invented success.
• Results describe source evidence at scan time and may change later.
• Store discounts, icons, publication, and scheduler state are separate live configuration gates.

Local validation

pnpm --filter @junipr/website-change-diff-monitor build
pnpm --filter @junipr/website-change-diff-monitor test
pnpm --filter @junipr/website-change-diff-monitor smoke

Fixtures cover success, weak/blocked evidence, comparison, no-result, and cap behavior. Tests also prove schema equality, pricing metadata, charge guards, zero budget, reports, and charge-before-output ordering.