# StableEmail Send (Shared Domain)

> StableEmail Send (Shared Domain) is a paid API for AI agents from stableemail.dev, paid per call via MPP or x402, $0.02/call, status unknown (last checked 2026-09-14, last successful call 2026-06-04).

Sends an email from a shared stableemail.dev domain via the StableEmail API

## Facts

- Endpoint: POST https://stableemail.dev/api/send
- Price: $0.02/call
- Payment: MPP, x402
- Status: unknown
- Last checked: 2026-09-14
- Last successful call: 2026-06-04
- Success rate: 87% of calls made through Zero
- Rating: 4.4 / 5 from 10 reviews
- Activations on Zero: 95
- Tags: x402
- Canonical page: https://www.zero.xyz/c/stableemail-eb3f7fdf
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Qs4C_qQXA8yB3JMveZ9uo

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 stableemail-eb3f7fdf -d '<json body>'
```

Example prompt: Send an email to alice@example.com with the subject 'Your order has shipped' and the message body 'Hi Alice, your package is on its way and should arrive by Friday. Thanks for your order!' using the StableEmail shared domain.

## When to prefer this

Use this endpoint when you need to send a one-off or automated email quickly without setting up a custom domain or inbox. It is ideal for agent workflows, transactional notifications, or lightweight email delivery where a shared stableemail.dev sender address is acceptable. Choose the custom inbox send endpoints if you need a branded sender address.

## Known failure modes

- Invalid or malformed recipient email address returns a 4xx error
- Insufficient USDC balance or failed x402 payment results in payment error
- Missing required fields (recipient, subject, body) returns a validation error
- Rate limiting or abuse detection may block repeated sends
- Shared domain may trigger spam filters at recipient mail servers

## How this service works

Send email (shared domain)

## Output

A confirmation response indicating whether the email was successfully delivered, along with a message ID or send status from the StableEmail API.

## Example request

```json
{
 "to": [
  "zero-qa@agentmail.to"
 ],
 "text": "This is a test email to verify the StableEmail API is functioning correctly.",
 "subject": "Test Email from StableEmail API",
 "username": "testuser123"
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "cc": {
   "type": "array",
   "items": {
    "type": "string",
    "format": "email",
    "pattern": "^(?!\\.)(?!.*\\.\\.)([A-Za-z0-9_'+\\-\\.]*)[A-Za-z0-9_+-]@([A-Za-z0-9][A-Za-z0-9\\-]*\\.)+[A-Za-z]{2,}$"
   },
   "maxItems": 50,
   "minItems": 1
  },
  "to": {
   "type": "array",
   "items": {
    "type": "string",
    "format": "email",
    "pattern": "^(?!\\.)(?!.*\\.\\.)([A-Za-z0-9_'+\\-\\.]*)[A-Za-z0-9_+-]@([A-Za-z0-9][A-Za-z0-9\\-]*\\.)+[A-Za-z]{2,}$"
   },
   "maxItems": 50,
   "minItems": 1
  },
  "html": {
   "type": "string",
   "maxLength": 256000
  },
  "text": {
   "type": "string",
   "maxLength": 256000
  },
  "replyTo": {
   "type": "string",
   "format": "email",
   "pattern": "^(?!\\.)(?!.*\\.\\.)([A-Za-z0-9_'+\\-\\.]*)[A-Za-z0-9_+-]@([A-Za-z0-9][A-Za-z0-9\\-]*\\.)+[A-Za-z]{2,}$"
  },
  "subject": {
   "type": "string",
   "maxLength": 998,
   "minLength": 1
  },
  "attachments": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "content",
     "contentType",
     "filename"
    ],
    "properties": {
     "content": {
      "type": "string",
      "maxLength": 5000000
     },
     "filename": {
      "type": "string",
      "maxLength": 255,
      "minLength": 1
     },
     "contentType": {
      "type": "string",
      "maxLength": 255,
      "minLength": 1
     }
    },
    "additionalProperties": false
   },
   "maxItems": 5
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/stableemail-eb3f7fdf/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from stableemail.dev](https://www.zero.xyz/host/stableemail.dev/llms.txt)