# Crier SMS API

> Crier SMS API is a paid API for AI agents from crier.vimabrosta.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-16).

Sends an opt-in-gated SMS message (up to 300 characters) from an AI agent to a specified E.164 phone number, with automatic opt-out suffix and retry logic.

## Facts

- Endpoint: POST https://crier.vimabrosta.com/v1/sms?utm_source=zero.xyz
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/crier-sms-api-aaeb5dd8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_cLOq9OVNjrlfkwMCkwmzZ

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-sms-api-aaeb5dd8 -d '<json body>'
```

Example prompt: Text +12125550198 to let them know their order has shipped and will arrive tomorrow — keep it under 300 characters.

## When to prefer this

Choose this endpoint when an AI agent needs to deliver a one-way SMS notification to a human who has already opted in by texting CRIER from their handset. It is ideal for lightweight, low-frequency alerts (up to 6/day) where no account setup is desired and a one-time $0.05 micropayment per message is acceptable. Prefer alternatives if you need two-way SMS, higher volume throughput, or the ability to initiate opt-in from the agent side.

## Known failure modes

- Recipient number has not opted in by texting CRIER to the relay — message not sent
- Rate limit exceeded: more than 2 messages per hour or 6 per day to the same number
- Invalid E.164 format for the 'to' field — request rejected
- Message text exceeds 300 characters — request rejected
- Recipient has previously sent STOP — delivery permanently blocked for all senders
- Payment of $0.05 USDC not provided or rejected — request fails

## How this service works

Send an SMS from an AI agent to a phone number (E.164): up to 300 characters, from a fixed relay number with an opt-out suffix, retried on failure, with a status endpoint you can poll. The number must have opted in first by texting CRIER to the relay from that handset; an agent cannot text a number to ask. STOP ends it for every sender. Up to 2 per hour, 6 per day. One-time $0.05, no account.

## Output

Returns a status response with a polling endpoint URL so the agent can check whether the SMS was successfully delivered or is still being retried. The message is sent from a fixed relay number with an opt-out suffix automatically appended.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "required": [
      "to",
      "text"
     ],
     "properties": {
      "to": {
       "type": "string",
       "pattern": "^\\+[1-9][0-9]{6,14}$",
       "description": "E.164: a plus sign, then 7 to 15 digits."
      },
      "text": {
       "type": "string",
       "maxLength": 300,
       "description": "An opt-out suffix is appended."
      }
     }
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/crier-sms-api-aaeb5dd8/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)