# StableEmail Inbox Topup (30 Days)

> StableEmail Inbox Topup (30 Days) is a paid API for AI agents from StableEmail at stableemail.dev, paid per call via MPP, $1/call, status unknown (last checked 2026-10-12).

Extends a StableEmail forwarding inbox's active period by 30 days for $1 USDC

## Facts

- Endpoint: POST https://stableemail.dev/api/inbox/topup?utm_source=zero.xyz
- Price: $1/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Provider: StableEmail
- Docs: https://stableemail.dev
- Website: https://stableemail.dev
- Tags: email, send, inbox, forwarding, subdomain, social
- Canonical page: https://www.zero.xyz/c/stableemail-topup-3144ae15
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6h2ihlK_btKpTLrC20UH7

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-topup-3144ae15 -d '<json body>'
```

Example prompt: Top up my StableEmail forwarding inbox 'myusername' for another 30 days — charge the $1 renewal now so it doesn't expire.

## When to prefer this

Use this endpoint when you need to renew a StableEmail forwarding inbox for a standard 30-day period at $1. If you need a longer renewal period, prefer the Year endpoint which offers 365 days for $8 (34% savings).

## Known failure modes

- Username not found — inbox does not exist or was deleted
- Invalid username format — must be lowercase alphanumeric with hyphens, no consecutive hyphens
- Payment failure — insufficient USDC balance or payment protocol error
- Inbox already expired beyond recovery window

## How this service works

Top up a forwarding inbox for 30 days ($1)

## Output

Confirmation that the forwarding inbox has been extended by 30 days, with updated expiry information.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "username"
 ],
 "properties": {
  "username": {
   "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-topup-3144ae15/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)