Website Change Monitoring API

Try it

curl -X POST "https://api.rasterly.dev/v1/monitors" \
  -H "X-Api-Key: sk_live_..." \
  -H "content-type: application/json" \
  -d '{
    "url": "https://shop.example/p/42",
    "mode": "selector",
    "selector": ".price",
    "interval_minutes": 30,
    "webhook": "https://your-app.com/hooks/rasterly"
  }'

{
  "event": "monitor.changed",
  "id": "bd67542f-...",
  "url": "https://shop.example/p/42",
  "mode": "selector",
  "changed": true,
  "hash": "6a2641...",
  "previous_hash": "4e1c48...",
  "sample": "$79.00",
  "checked_at": "2026-08-19T08:00:00Z"
}

Three modes

• content — hashes the page's clean Markdown. Any copy/content change fires. Good for news, docs, ToS, job posts.
• selector — hashes one CSS selector's text. Alert only on that — a price, a stock badge, a status line, a version number.
• visual — hashes a screenshot. Any pixel change fires; broadest and noisiest, good for defacement / layout watches.

Manage them

• GET /v1/monitors — list all monitors with their last check + change counts.
• POST /v1/monitors/:id/check — force a check now (test your webhook, or poll on demand).
• DELETE /v1/monitors/:id — stop watching.

What it's for

• Price-drop & stock alerts — watch a .price or "In stock" selector and fire the moment it moves.
• Competitor monitoring — know when a rival changes pricing, ships a feature, or edits a landing page.
• Status & defacement — visual-watch a page and alert on any unexpected change.
• Compliance & docs — get notified when a terms-of-service or policy page is edited.

Why rasterly

Same render engine as the rest of the toolkit, so checks handle modern JS pages and cost about a second of CPU each. Monitoring is a small monthly subscription per set of monitors rather than a per-call fee — predictable, and it pairs naturally with the structured-data and screenshot endpoints you may already use.

FAQ