# StableSchedule Webhook Cron Topup

> StableSchedule Webhook Cron Topup is a paid API for AI agents from stableschedule.dev, paid per call via x402, $1/call, status unknown (last checked 2026-09-14).

Creates or tops up a prepaid cron-scheduled HTTP webhook job, purchasing a bundle of scheduled runs with a cron expression and target request definition.

## Facts

- Endpoint: POST https://stableschedule.dev/api/schedule/topup
- Price: $1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/stableschedule-webhook-cron-topup-7332a2af
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0laTk2mREUPug6Y6NX1bZ

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 stableschedule-webhook-cron-topup-7332a2af -d '<json body>'
```

Example prompt: Set up a StableSchedule cron job that POSTs to https://myapp.example.com/daily-report every day at midnight UTC — buy the 1k run bundle — and call it 'Daily Report Job'.

## When to prefer this

Choose this endpoint when you need to schedule recurring HTTP webhook calls on a cron schedule and want prepaid, usage-based billing via USDC rather than a subscription. Ideal for automating periodic API calls, background jobs, or timed notifications without managing your own cron infrastructure.

## Known failure modes

- Invalid cron expression — returns error if the cron string is malformed or empty
- Missing required fields (cron, sku, or request.url) — returns validation error
- Invalid SKU value — must be '1k', '10k', or '100k'
- Webhook URL not reachable or malformed — may fail at registration or on first fire
- Payment failure — x402 payment of $1 USDC not completed or rejected
- timeout_ms out of range (must be 1000–30000) — returns validation error
- Request headers values exceeding 4096 characters — rejected by schema validation

## How this service works

Prepaid cron scheduling for HTTP webhooks.

## Output

Returns a JSON object with the schedule ID (e.g. 'sch_example'), the schedule status ('active'), the SKU tier purchased, the number of runs added (e.g. 1000 for '1k'), and the full credits breakdown showing total, used, and remaining runs.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "sku": {
   "enum": [
    "1k",
    "10k",
    "100k"
   ],
   "type": "string"
  },
  "schedule_id": {
   "type": "string",
   "minLength": 1
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "status": "active",
  "credits": {
   "used": 250,
   "total": 2000,
   "remaining": 1750
  },
  "added_runs": 1000,
  "schedule_id": "sch_example"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/stableschedule-webhook-cron-topup-7332a2af/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from stableschedule.dev](https://www.zero.xyz/host/stableschedule.dev/llms.txt)