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Forest Web – Detect Changes in Static Page
x402
Forest Web – Detect Changes in Static Page is a paid API for AI agents from http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run, paid per call via x402, $0.004/call, status unknown (last checked 2026-10-12).
Detects bounded, deterministic changes across a static HTML page by comparing multi-dimensional SHA-256 hashes (HTTP identity, metadata, JSON-LD, links, forms, robots) against a previously captured baseline.
Price / call$0.004
Success—
StatusUnknown
How this service works
Detect bounded changes across one static page surface using one HTML fetch plus at most one robots.txt fetch. Forest hashes HTTP identity, page metadata, normalized JSON-LD, downloadable links, form schema and robots context without storing snapshots, rendering JavaScript or submitting anything. Base mainnet USDC
Output
Returns a change detection result indicating whether the page has materially changed since the previous hash was recorded, along with dimension-level comparisons (HTTP identity, page metadata, normalized JSON-LD, downloadable links, form schema, and robots context) — without storing snapshots, executing JavaScript, or submitting any forms.
Example use cases
Job listing change detection
“Tell me if the job posting at https://careers.acme.com/jobs/12345 has changed since yesterday — I have the previous combined hash sha256:9f1a2b...cc44 and the previous dimension hashes for http, page, structured, downloads, forms, and robots from my last check.”
Product page price or metadata update
“Has the product page at https://shop.brand.com/product/widget changed at all since my last scan? Use my previous full hash sha256:de2f44...b901 and my previous dimension hashes to tell me which specific parts changed.”
Documentation page structure monitoring
“I want to know if the docs page at https://docs.myapi.com/reference has been updated — compare it against these previous hashes for all six dimensions and tell me if anything is different.”
Technical details
Endpoint
POSThttps://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/site/changed-since?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need lightweight, deterministic, privacy-safe change detection on a static HTML page without storing full snapshots. It is ideal for monitoring pages where you already have a previous hash baseline and want to know precisely which dimension (metadata, links, forms, JSON-LD, robots) changed, rather than extracting full content. Prefer this over full-extraction endpoints when bandwidth or cost matters and you only need a changed/unchanged signal with dimension-level granularity.
Side effects
- Invalid or inaccessible URL returns an error
- Malformed previous_hash pattern (not sha256:[64 hex chars]) causes a validation rejection
- Page requires JavaScript rendering — result will reflect static HTML only, dynamic content not captured
- robots.txt fetch may fail silently if not present, affecting robots dimension hash
- Payment not included or invalid returns HTTP 402
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| url | string | Public HTTP(S) URL to inspect, resolve, or compare. |
| user_agent | string | Public user agent value used to scope this lookup. |
| previous_hash | string | Earlier result hash used to detect a material change. |
| previous_dimensions | object | Public previous dimensions value used to scope this lookup. |
Tags
x402
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