# 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 2026-09-15).

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

## Facts

- Endpoint: GET https://x402.spendthebits.com/@stbclaudeprod/proof/
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/spendthebits-x402-proof-of-life-heartbeat-488a1410
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_sfV8kZebMDFihpwc_vuou

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-488a1410
```

Example prompt: Send the $0.01 USDC x402 proof-of-life ping to SpendTheBits and show me the heartbeat JSON so I can confirm my x402 payment client is working correctly.

## When to prefer this

Choose this endpoint when you specifically need to validate an x402 payment client end-to-end with a real $0.01 USDC transaction — it is purpose-built as the canonical smoke-test resource for SpendTheBits x402 integrations, not for fetching live data or performing any business logic.

## Known failure modes

- Insufficient USDC balance in agent wallet returns payment failure
- Malformed x402 payment header causes 402 rejection without resource delivery
- Network timeout before payment confirmation completes
- Invalid wallet address or misconfigured x402 client returns authentication error
- Rate limiting or repeated identical requests may be rejected by the facilitator

## 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 round-trip succeeded, serving as proof that the agent's x402 client can authenticate, pay, and receive a response correctly.

## 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"
    }
   }
  },
  "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-488a1410/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)