# SYNTHORA x402 Registry Watch

> SYNTHORA x402 Registry Watch is a paid API for AI agents from regwatch.hergertsynthora.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-14).

Streams signed Ed25519 delta events from the live x402/M2M endpoint registry, including endpoint changes, payTo address updates, listings, and price changes, with verifiable provenance receipts per response.

## Facts

- Endpoint: POST https://regwatch.hergertsynthora.com/service
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synthora-x402-registry-watch-d101f993
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_267XaP3sZ96IHxm8P3gZD

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 synthora-x402-registry-watch-d101f993 -d '<json body>'
```

Example prompt: Give me the latest x402 registry changes since cursor del_abc123, filtered to the 'defi-data' market slug, up to 50 events — and include the Ed25519 receipt so I can verify the provenance.

## When to prefer this

Choose this endpoint when you need cryptographically verifiable, signed delta feeds of the x402/M2M endpoint registry — especially for router agents or discovery services that require tamper-evident provenance receipts and need to efficiently poll only changes since a known cursor rather than fetching the full registry. Ideal when building automated x402 routing or arbitrage agents that need to react to price or listing changes in real time.

## Known failure modes

- Invalid or expired 'since' cursor returns an error or empty result set
- Unknown market slug returns empty results or 400 error
- Payment not received (x402 protocol) causes 402 response blocking access
- Malformed timestamp in 'since' field causes parsing error
- Rate limiting or overload may return 5xx response
- Ed25519 signature verification failure on client side if receipt is tampered

## How this service works

Real-time x402 endpoint discovery and M2M market-data feed: x402 endpoint delta feed, payTo address changes, x402 service listings live, x402 registry diff and x402 index deltas. Pay-per-event feed for router-agent price feed consumers; every response is Ed25519-signed with per-row and whole-response provenance receipt.

## Output

Returns an object with 'ok' boolean, a 'result' containing delta events (endpoint additions, removals, payTo address changes, price updates) since the specified cursor or timestamp, and a 'receipt' object with Ed25519 signatures for per-row and whole-response provenance verification.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "slug": {
   "type": "string"
  },
  "limit": {
   "type": "integer"
  },
  "since": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "niche": "registry_watch",
  "result": {
   "feed": [],
   "as_of": "2026-08-05T16:48:43Z",
   "count": 0,
   "cursor": null,
   "source": "registry-watch"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/synthora-x402-registry-watch-d101f993/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from regwatch.hergertsynthora.com](https://www.zero.xyz/host/regwatch.hergertsynthora.com/llms.txt)