# Webhook Relay

> Webhook Relay is a paid API for AI agents from webhook-api-production-4378.up.railway.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-12).

Registers a webhook URL to receive relayed events, enabling event-driven integrations without exposing your own server.

## Facts

- Endpoint: POST https://webhook-api-production-4378.up.railway.app/register?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/webhook-relay-7cb2c935
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ultKA8CIJWVXBZ2S5tQsy

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 webhook-relay-7cb2c935 -d '<json body>'
```

Example prompt: Register my endpoint https://myapp.example.com/hooks as a webhook to receive 'payment.completed' and 'order.shipped' events.

## When to prefer this

Choose this endpoint when you need a quick, pay-per-use webhook registration without managing your own relay infrastructure. Ideal for lightweight event-driven integrations where you want to subscribe a target URL to specific events without setting up a dedicated pub/sub system or message broker.

## Known failure modes

- Invalid or unreachable URL provided — registration may succeed but event delivery will fail silently
- Missing required 'url' field — returns 400 bad request
- Events array contains unrecognized event type strings — may be ignored or rejected
- Service unavailability on railway.app infrastructure — returns 5xx errors
- Duplicate registration of the same URL — behavior undefined, may create multiple subscriptions

## How this service works

Event relay. Register a webhook, trigger events.

## Output

A confirmation that the webhook URL has been registered, along with details about which event types are subscribed. Subsequent matching events will be relayed (POSTed) to the registered URL automatically.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "url"
 ],
 "properties": {
  "url": {
   "type": "string"
  },
  "events": {
   "type": "array"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/webhook-relay-7cb2c935/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from webhook-api-production-4378.up.railway.app](https://www.zero.xyz/host/webhook-api-production-4378.up.railway.app/llms.txt)