# SpendTheBits x402 Proof-of-Life Heartbeat

> SpendTheBits x402 Proof-of-Life Heartbeat is a paid API for AI agents from x402.spendthebits.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-20).

Returns a JSON heartbeat for $0.01 USDC to verify an agent's x402 payment client is working end-to-end.

## Facts

- Endpoint: GET https://x402.spendthebits.com/@superappstb/proof/?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/spendthebits-x402-proof-of-life-heartbeat-321b8cfa
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-v5q5Elz28WANhecZZD8S

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 spendthebits-x402-proof-of-life-heartbeat-321b8cfa
```

Example prompt: Make a $0.01 proof-of-life payment to the SpendTheBits x402 heartbeat endpoint so I can confirm my x402 payment client is wired up correctly end to end.

## When to prefer this

Use this endpoint specifically when you need to verify that an x402 payment client is correctly configured and capable of completing a real micropayment transaction. It is purpose-built as a cheap ($0.01) end-to-end integration test for x402 flows — not for testing general HTTP connectivity or non-payment API integrations.

## Known failure modes

- Payment rejected if x402 client is misconfigured or missing payment header
- Insufficient funds in agent wallet causes payment failure
- Network timeout or connectivity issue to x402.spendthebits.com
- Invalid x402 protocol version mismatch
- Rate limiting or server-side errors returning non-200 status

## How this service works

Official $0.01 proof-of-life resource for SpendTheBits x402: returns a JSON heartbeat. Pay it to verify your agent's x402 client end to end.

## Output

A JSON heartbeat object confirming the x402 payment was accepted and the service is alive; serves as proof that the agent's x402 payment client completed a real end-to-end payment transaction successfully.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "method": {
     "type": "string"
    },
    "queryParams": {
     "type": "object"
    }
   }
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/spendthebits-x402-proof-of-life-heartbeat-321b8cfa/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.spendthebits.com](https://www.zero.xyz/host/x402.spendthebits.com/llms.txt)