# Fastsend SMS & Email Messaging API

> Fastsend SMS & Email Messaging API is a paid API for AI agents from fastsend.dev, paid per call via x402, $0.165/call, status unknown (last checked 2026-10-03).

Send an SMS or email message to a specified recipient via Fastsend's messaging platform.

## Facts

- Endpoint: POST https://fastsend.dev/api/v2/messages?utm_source=zero.xyz
- Price: $0.165/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-03
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fastsend-sms-email-messaging-api-414328f3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_CIdfv4ihpHLycp7x9BKgJ

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 fastsend-sms-email-messaging-api-414328f3 -d '<json body>'
```

Example prompt: Send an SMS to +14155552671 from +14155550100 saying 'Your order has shipped and will arrive tomorrow!'

## When to prefer this

Choose this endpoint when you need a simple, pay-per-use API to programmatically send either SMS or email messages without managing your own carrier integrations or email infrastructure. It is ideal for agentic workflows that need to notify, alert, or reach users on-demand, especially when cost predictability ($0.165 per message) and dual-channel support (SMS + email) in a single API call matters.

## Known failure modes

- Invalid or unformatted phone number or email address returns a validation error
- Missing required fields (to, from, channel, content) result in a 400 bad request
- Unsupported channel value (not 'sms' or 'email') causes rejection
- Payment not completed (x402 protocol) blocks the request
- Rate limiting or quota exceeded returns a 429 error
- Delivery failure to the recipient's carrier or email provider may result in a non-delivery report

## How this service works

Send an SMS or email message via Fastsend.

## Output

A confirmation response indicating whether the message was successfully dispatched, typically including delivery status and message metadata such as message ID.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "to": {
   "type": "string"
  },
  "from": {
   "type": "string"
  },
  "channel": {
   "enum": [
    "sms",
    "email"
   ],
   "type": "string"
  },
  "content": {
   "type": "string"
  },
  "subject": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fastsend-sms-email-messaging-api-414328f3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fastsend.dev](https://www.zero.xyz/host/fastsend.dev/llms.txt)