# OnchainExpat x402 SMS Send

> OnchainExpat x402 SMS Send is a paid API for AI agents from x402.onchainexpat.com, paid per call via x402, $3.5/call, status unknown (last checked 2026-09-13, last successful call 2026-07-11).

Sends an SMS message to a specified phone number via pay-per-request x402 protocol payment

## Facts

- Endpoint: POST https://x402.onchainexpat.com/api/x402-sms/send
- Price: $3.5/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Last successful call: 2026-07-11
- Success rate: 50% of calls made through Zero
- Activations on Zero: 2
- Tags: x402
- Canonical page: https://www.zero.xyz/c/onchainexpat-x402-sms-send-964c0fd5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_C4sg7KIklJU6teMB8roTI

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 onchainexpat-x402-sms-send-964c0fd5 -d '<json body>'
```

Example prompt: Send an SMS to +14155552671 with the message: 'Your order has been shipped and will arrive tomorrow.'

## When to prefer this

Choose this endpoint when you need to send a single SMS message programmatically without committing to a monthly SMS subscription service, paying only $3.50 USDC per message via the x402 micropayment protocol. It is ideal for AI agents, bots, or automated workflows that send infrequent or on-demand notifications and want crypto-native billing.

## Known failure modes

- Invalid or non-E.164 formatted phone number returns an error
- Message body exceeds SMS character limits causes rejection
- Insufficient x402 payment (not enough USDC) results in 402 Payment Required
- Carrier rejection or undeliverable number returns a failed status
- Network or upstream SMS provider outage causes delivery failure

## How this service works

Pay-per-request AI, crypto, proxy, and utility APIs using x402 protocol

## Output

Returns a JSON object with the recipient phone number, delivery status string, and a unique message ID for tracking.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "to",
  "message"
 ],
 "properties": {
  "to": {
   "type": "string",
   "description": "E.164 phone number to send SMS to"
  },
  "message": {
   "type": "string",
   "description": "Message body (SMS character limits apply)"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "to": {
   "type": "string"
  },
  "status": {
   "type": "string"
  },
  "message_id": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/onchainexpat-x402-sms-send-964c0fd5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.onchainexpat.com](https://www.zero.xyz/host/x402.onchainexpat.com/llms.txt)