# Greenhead Labs x402 Base Mainnet Ping

> Greenhead Labs x402 Base Mainnet Ping is a paid API for AI agents from x402.greenhead.io, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-15).

Validates that the x402 payment-gated route on Base mainnet USDC is live and reachable by completing a full facilitator verify-and-settle cycle and returning HTTP 200.

## Facts

- Endpoint: GET https://x402.greenhead.io/v1/base/ping
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/greenhead-labs-x402-base-mainnet-ping-a6294a2d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0lAVsGCIZFzHkJxT67t08

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 greenhead-labs-x402-base-mainnet-ping-a6294a2d
```

Example prompt: Ping the Greenhead Labs x402 route on Base mainnet to confirm the USDC payment flow is working end-to-end — I want to verify the facilitator can successfully settle a 0.002 USDC charge.

## When to prefer this

Choose this endpoint when you need to validate that an x402 payment-gated API on Base mainnet is operational end-to-end, including the full facilitator verify-and-settle cycle. It is the cheapest available x402 SKU (0.002 USDC), making it ideal for health checks, smoke tests, and integration validation without significant cost. Prefer it over generic HTTP health checks when you specifically need to confirm that USDC micropayment acceptance and settlement are working on Base (eip155:8453), not just that the server is reachable.

## Known failure modes

- HTTP 402 returned if the x402 payment header is missing or malformed — agent must attach a valid Base mainnet USDC payment
- HTTP 402 if wallet has insufficient USDC balance to cover the 0.002 USDC charge
- Facilitator settle failure if Base mainnet is congested or the facilitator service is degraded
- Timeout if the Base RPC endpoint is slow to confirm the on-chain settlement
- HTTP 500 if the Greenhead Labs backend is unavailable

## How this service works

Prove route for Base mainnet USDC x402 (eip155:8453). HTTP 200 after facilitator verify+settle. Priced as the cheapest SKU (0.002 face → 2000 USDC atomic when Base is enabled).

## Output

An HTTP 200 response confirming that the x402 payment-gated route on Base mainnet accepted the USDC micropayment, the facilitator completed verify and settle, and the route is fully operational. No meaningful payload body beyond the status confirmation.

## 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",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/greenhead-labs-x402-base-mainnet-ping-a6294a2d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.greenhead.io](https://www.zero.xyz/host/x402.greenhead.io/llms.txt)