# Agent Fetch Hub — Diff Endpoint (Web Page Change Detection)

> Agent Fetch Hub — Diff Endpoint (Web Page Change Detection) is a paid API for AI agents from fetch.netzhandwerker.de, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).

Fetches a URL and returns a diff or change-detection result as clean Markdown, paid per-call in USDC over x402 with no signup required.

## Facts

- Endpoint: POST https://fetch.netzhandwerker.de/diff
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent-fetch-hub-diff-endpoint-web-page-change-detection-2292b272
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_rDf7U8T1mcQ4UynBzWJAD

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-fetch-hub-diff-endpoint-web-page-change-detection-2292b272 -d '<json body>'
```

Example prompt: Can you check https://example.com/pricing and give me a diff showing what's changed on that page — I want to see any content differences detected?

## When to prefer this

Choose this endpoint when you need to detect or compare changes on a specific web page without any signup or API key, and you want to pay only per successful call in USDC. It is ideal for agents that need lightweight, on-demand change detection on arbitrary URLs without maintaining a subscription or credentials.

## Known failure modes

- Invalid or unreachable URL returns an error response
- Payment failure via x402 protocol blocks the request
- Rate limiting if too many calls are made in quick succession
- Pages behind authentication or CAPTCHAs may not be accessible
- Empty diff if no changes are detected or no baseline exists

## How this service works

URL in, clean Markdown out. Pay per call in USDC over x402. No signup, no API key.

## Output

A JSON response with an 'ok' boolean and diff/change-detection data showing what content on the target URL has changed, returned as structured JSON (potentially including Markdown-formatted diff content).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "format": "uri",
   "description": "Page to fetch and compare against its last stored state."
  },
  "after": {
   "type": "string",
   "description": "Later document as HTML or Markdown."
  },
  "since": {
   "type": "string",
   "format": "date-time",
   "description": "ISO timestamp. Picks the stored state at or before this moment instead of the newest one."
  },
  "before": {
   "type": "string",
   "description": "Earlier document as HTML or Markdown. No network access is used."
  },
  "after_fetched_at": {
   "type": "string",
   "format": "date-time",
   "description": "Optional, echoed back for inline comparisons."
  },
  "before_fetched_at": {
   "type": "string",
   "format": "date-time",
   "description": "Optional, echoed back for inline comparisons."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent-fetch-hub-diff-endpoint-web-page-change-detection-2292b272/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fetch.netzhandwerker.de](https://www.zero.xyz/host/fetch.netzhandwerker.de/llms.txt)