# Agent Market Lab Website Change Check

> Agent Market Lab Website Change Check is a paid API for AI agents from agent-market-lab.fidelly.eu, paid per call via x402, $0.1/call, status unknown (last checked 2026-10-12).

Snapshots a public URL and compares it to a previous baseline snapshot to detect whether the page content has changed.

## Facts

- Endpoint: POST https://agent-market-lab.fidelly.eu/v1/website-change-check?utm_source=zero.xyz
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent-market-lab-website-change-check-52e4b70c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_dH5T_poMBdouAN-4arcnG

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-website-change-check-52e4b70c -d '<json body>'
```

Example prompt: Check whether https://example.com/pricing has changed since last time — compare it against my previous snapshot ID 123e4567-e89b-42d3-a456-426614174000 and tell me if anything is different.

## When to prefer this

Use this endpoint when you need lightweight, pay-per-call website change detection without committing to a subscription monitoring service. Ideal for autonomous agents that need to check a specific URL on demand, compare against a stored baseline, and get a clear changed/unchanged signal with a content hash. Prefer this over full web-scraping endpoints when your goal is purely detecting mutations rather than extracting structured data.

## Known failure modes

- URL is not publicly reachable (returns error or empty snapshot)
- Invalid or mismatched baselineId UUID causes comparison failure
- Dynamically rendered JavaScript pages may yield unreliable content hashes
- Rate limiting or payment failure via x402 blocks the request
- URL exceeds 2048-character limit returns validation error
- Paywalled or bot-protected pages may return blocked/empty content

## 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 a boolean 'changed' flag, a content hash of the current page, the new snapshot ID, a creation timestamp, optional diff details in 'changes', and the baseline snapshot metadata for comparison.

## 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": {
  "ok": true,
  "data": {
   "url": "https://example.com/",
   "changed": null,
   "changes": null,
   "current": {},
   "baseline": null,
   "createdAt": "2026-10-09T00:00:00.000Z",
   "snapshotId": "123e4567-e89b-42d3-a456-426614174000",
   "contentHash": "sha256-example"
  },
  "tool": "monitor_website_changes",
  "requestId": "123e4567-e89b-42d3-a456-426614174000"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent-market-lab-website-change-check-52e4b70c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent-market-lab.fidelly.eu](https://www.zero.xyz/host/agent-market-lab.fidelly.eu/llms.txt)