# Crier Webhook Delivery

> Crier Webhook Delivery is a paid API for AI agents from crier.vimabrosta.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-18).

Delivers a signed, retried HTTP webhook from an AI agent to any public URL, with HMAC verification and a pollable status endpoint, for a flat $0.005 fee.

## Facts

- Endpoint: POST https://crier.vimabrosta.com/v1/webhook
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/crier-webhook-delivery-2f360ace
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_QI9fPYyaKMSAaprWIoSH1

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 crier-webhook-delivery-2f360ace -d '<json body>'
```

Example prompt: Send a signed webhook with this JSON payload to https://hooks.myapp.com/orders/new using POST — I need it retried automatically if the server is down, and I want to be able to check delivery status afterward.

## When to prefer this

Choose this endpoint when an AI agent needs to reliably notify an external HTTP endpoint — especially after the agent session may have ended — with built-in retry logic and HMAC signature verification. It's ideal over a raw HTTP POST when delivery reliability, tamper-evidence, and asynchronous status checking matter, and when you don't want to manage retry infrastructure yourself. The flat $0.005 one-time fee with no account setup makes it suited for lightweight, fire-and-forget agent workflows.

## Known failure modes

- Receiver URL is not publicly reachable — delivery fails after all retries are exhausted
- Body exceeds 16KB limit — request rejected
- Custom header names do not start with X- or start with X-Crier- — request rejected
- Invalid URL format provided — request rejected immediately
- More than 5 custom headers provided — request rejected
- Receiver returns non-2xx on every retry attempt — final delivery failure recorded in status endpoint

## How this service works

Deliver a signed webhook from an AI agent to a public URL: JSON or text body up to 16KB, POST or PUT, optional custom X- headers. Retried at 30 s, 2 m, 10 m, 1 h, and 6 h after your session is gone, HMAC signed with a one-time secret so the receiver can verify it, with a status endpoint you can poll. One-time $0.005, no account needed.

## Output

Returns a delivery job ID and a status URL you can poll to check whether the webhook was successfully delivered. The payload is HMAC-signed with a one-time secret so the receiver can verify authenticity. If delivery fails, the system retries at 30 seconds, 2 minutes, 10 minutes, 1 hour, and 6 hours after the agent session ends.

## Request schema (JSON Schema)

```json
{
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "type": "object",
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "type": "string",
     "enum": [
      "POST"
     ]
    },
    "bodyType": {
     "type": "string",
     "enum": [
      "json",
      "form-data",
      "text"
     ]
    },
    "body": {
     "type": "object",
     "required": [
      "url",
      "body"
     ],
     "properties": {
      "url": {
       "type": "string",
       "format": "uri",
       "description": "Public http(s) receiver."
      },
      "method": {
       "type": "string",
       "enum": [
        "POST",
        "PUT"
       ],
       "default": "POST"
      },
      "body": {
       "description": "A JSON value (sent as application/json) or a string (sent as text/plain unless content_type says otherwise). 16KB max."
      },
      "content_type": {
       "type": "string"
      },
      "headers": {
       "type": "object",
       "description": "Up to 5 custom headers; names must start with X- and not X-Crier-."
      }
     }
    }
   },
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   },
   "required": [
    "type"
   ]
  }
 },
 "required": [
  "input"
 ]
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/crier-webhook-delivery-2f360ace/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from crier.vimabrosta.com](https://www.zero.xyz/host/crier.vimabrosta.com/llms.txt)