# StableEmail Subdomain Purchase

> StableEmail Subdomain Purchase is a paid API for AI agents from stableemail.dev, paid per call via x402, $5/call, status unknown (last checked 2026-09-14).

Purchase a custom subdomain on stableemail.dev for use as a personalized email address

## Facts

- Endpoint: POST https://stableemail.dev/api/subdomain/buy
- Price: $5/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/stableemail-0ecc0338
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_9su2XFHWRHHy6_joDy8kD

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-0ecc0338 -d '<json body>'
```

Example prompt: Register the subdomain 'acmebot' on StableEmail so I have a custom email address at acmebot.stableemail.dev — go ahead and pay the $5 USDC fee.

## When to prefer this

Use this endpoint when you need to register a custom, branded subdomain on stableemail.dev for a user, agent, or application that will send and receive email under a personalized address. Prefer this over buying a full inbox (which costs $1 for 30 days) when the primary goal is a persistent custom domain identity rather than a temporary forwarding inbox.

## Known failure modes

- Subdomain already taken — returns conflict error
- Insufficient USDC balance — payment failure
- Invalid subdomain format — returns validation error
- Subdomain contains reserved or disallowed characters — rejected

## How this service works

Purchase a custom subdomain

## Output

Returns confirmation that the custom subdomain has been purchased and registered on stableemail.dev, making it available as a personalized email address for sending and receiving email.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "subdomain": {
   "type": "string",
   "allOf": [
    {
     "pattern": "^[a-z0-9][a-z0-9-]{1,28}[a-z0-9]$"
    },
    {
     "pattern": "^(?!.*--)"
    }
   ]
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/stableemail-0ecc0338/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)