# AgentMail Send Email Message

> AgentMail Send Email Message is a paid API for AI agents from x402.api.agentmail.to, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-09, last successful call 2026-07-10).

Sends an email message from a specified AI agent inbox via the AgentMail REST API

## Facts

- Endpoint: POST https://x402.api.agentmail.to/v0/inboxes/%7Binbox_id%7D/messages/send
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-09
- Last successful call: 2026-07-10
- Success rate: 100% of calls made through Zero
- Rating: 5.0 / 5 from 2 reviews
- Activations on Zero: 2
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentmail-send-email-message-72a567bc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5h5VKDAVUFg4xVQ1-BCVq

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 agentmail-send-email-message-72a567bc -d '<json body>'
```

Example prompt: Send an email from my AgentMail inbox (inbox ID: acct_123) to alice@example.com with the subject 'Project Update' and the body 'Hi Alice, just checking in on the project status — let me know if you need anything!'

## When to prefer this

Use this endpoint when an AI agent needs to send outbound email from a dedicated AgentMail inbox, especially in automated workflows where the agent is acting as an email participant. Prefer this over generic SMTP or transactional email APIs when the agent needs a persistent, addressable inbox identity and the x402 micropayment model fits the use case.

## Known failure modes

- Invalid or non-existent inbox_id returns 404 not found
- Missing required fields (recipient, subject, or body) returns 400 bad request
- Insufficient USDC balance or x402 payment failure prevents message dispatch
- Rate limiting or quota exceeded returns 429 too many requests
- Invalid recipient email format returns validation error
- Authentication failure returns 401 unauthorized

## How this service works

Service: AgentMail API (/v0/inboxes/{inbox_id}/messages/send)

## Output

Returns a JSON confirmation object with the sent message ID and delivery status, confirming the email was dispatched from the specified inbox.

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {}
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentmail-send-email-message-72a567bc/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.api.agentmail.to](https://www.zero.xyz/host/x402.api.agentmail.to/llms.txt)