# Agent Market Lab Web Data – Website Change Check

> Agent Market Lab Web Data – Website Change Check is a paid API for AI agents from agent-market-lab-v2.dourfer-r.workers.dev, paid per call via x402, $0.1/call, status unknown (last checked 2026-10-10).

Snapshots a public URL and detects whether its content has changed since a previous baseline snapshot, returning a diff and new snapshot ID.

## Facts

- Endpoint: POST https://agent-market-lab-v2.dourfer-r.workers.dev/v1/website-change-check?utm_source=zero.xyz
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent-market-lab-web-data-website-change-check-4b073f76
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_u10qgnpi42cn0Me9103cX

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability agent-market-lab-web-data-website-change-check-4b073f76 -d '<json body>'
```

Example prompt: Check if the page at https://example.com/pricing has changed since my last check — I got snapshot ID 3f2a1b4c-0000-0000-0000-abcdef123456 last time, use that as the baseline.

## When to prefer this

Choose this endpoint when you need to detect whether a specific public web page has changed between two points in time, especially when you already have a baseline snapshot ID from a prior call. It is ideal for autonomous agents that need to monitor individual URLs for content drift — pricing changes, availability updates, regulatory amendments — without building custom scraping infrastructure. Prefer this over generic scraping endpoints when change detection (diff) is the primary goal rather than full content extraction.

## Known failure modes

- URL is not publicly accessible or returns non-200 status — check/changes may be null
- Invalid or expired baselineId UUID — comparison may fall back to latest stored snapshot or return null
- Malformed URL input — 422 validation error
- Payment not completed via x402 — 402 Payment Required
- Rate limiting or Cloudflare Worker timeout for very large pages
- First-time URL with no stored snapshot — 'changed' and 'changes' will be null, only snapshotId is returned

## How this service works

Pay-per-call public-web extraction, ecommerce data including a 10-product batch, change detection and website business research for autonomous agents via x402 on Base.

## Output

Returns a JSON object with three fields: 'changed' (boolean or null if no prior snapshot exists to compare against), 'changes' (a description or diff of what changed, or null if unchanged/no baseline), and 'snapshotId' (a UUID for the freshly created snapshot, usable as a baseline in future calls).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "format": "uri",
   "maxLength": 2048,
   "description": "Absolute public HTTP or HTTPS URL to snapshot and compare."
  },
  "baselineId": {
   "type": "string",
   "format": "uuid",
   "description": "Optional snapshot ID previously returned for the same normalized URL. Omit to compare with the latest stored snapshot."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "changed": null,
  "changes": null,
  "snapshotId": "uuid"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent-market-lab-web-data-website-change-check-4b073f76/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent-market-lab-v2.dourfer-r.workers.dev](https://www.zero.xyz/host/agent-market-lab-v2.dourfer-r.workers.dev/llms.txt)