# StablePhone Phone Number Top-Up

> StablePhone Phone Number Top-Up is a paid API for AI agents from stablephone.dev, paid per call via x402, $15/call, status unknown (last checked 2026-09-13).

Extends the expiry of a purchased StablePhone phone number by 30 days from its current expiration date

## Facts

- Endpoint: POST https://stablephone.dev/api/number/topup
- Price: $15/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/stablephone-62e5da60
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_sUNePzwQd3IGQFYlUk1Cg

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 stablephone-62e5da60 -d '<json body>'
```

Example prompt: Top up my StablePhone number +14155551234 to extend it by 30 more days — go ahead and pay the $15 to keep it active.

## When to prefer this

Use this endpoint when you have an existing StablePhone dedicated number that is approaching its expiry date and need to extend it for another 30 days. Unlike buying a new number, this preserves the same phone number and caller ID. Top-ups can be stacked proactively before expiry. Choose this over re-purchasing when number continuity matters.

## Known failure modes

- Invalid or unrecognized phone number — number not found in StablePhone system
- Insufficient USDC balance or payment failure via x402 protocol
- Phone number already permanently cancelled and ineligible for renewal
- Network or API error returning 5xx status

## How this service works

Top up a phone number

## Output

A confirmation that the phone number's expiry has been extended by 30 days from its current expiry date. Top-ups stack, so multiple renewals can be applied in advance. Anyone can top up a number, not just the original purchaser.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "phone_number": {
   "type": "string",
   "pattern": "^\\+1\\d{10}$"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/stablephone-62e5da60/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from stablephone.dev](https://www.zero.xyz/host/stablephone.dev/llms.txt)