# StableEmail Inbox Annual Top-Up (365 Days)

> StableEmail Inbox Annual Top-Up (365 Days) is a paid API for AI agents from StableEmail at stableemail.dev, paid per call via MPP, $8/call, status unknown (last checked 2026-10-10, last successful call 2026-07-12).

Extends a StableEmail forwarding inbox subscription by 365 days for $8 USDC, offering a 34% discount over monthly renewals.

## Facts

- Endpoint: POST https://stableemail.dev/api/inbox/topup/year?utm_source=zero.xyz
- Price: $8/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-10
- Last successful call: 2026-07-12
- Success rate: 100% of calls made through Zero
- Activations on Zero: 1
- 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-year-635db01d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_1MQ0KUbIGZu3VFiasAr6y

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-year-635db01d -d '<json body>'
```

Example prompt: Top up my StableEmail forwarding inbox 'myusername' for a full year — I want the annual plan that saves 34%.

## When to prefer this

Use this endpoint when you want to renew a StableEmail forwarding inbox for a full year at a discounted rate ($8 vs $12 for 12 monthly top-ups). Prefer over the 30-day top-up when the inbox is expected to be used long-term and cost efficiency matters.

## Known failure modes

- Invalid username format — must be 3-30 lowercase alphanumeric characters with hyphens, no double hyphens
- Inbox does not exist for given username
- Payment failure or insufficient USDC balance
- Username violates pattern constraints (uppercase, special characters, double hyphens)

## How this service works

Top up a forwarding inbox for 365 days ($8, save 34%)

## Output

A confirmation that the forwarding inbox identified by the given username has been extended by 365 days, along with updated expiry information. Costs $8 USDC per call.

## 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-year-635db01d/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)