# gsc-x402.ai Payment Test Counterparty

> gsc-x402.ai Payment Test Counterparty is a paid API for AI agents from gsc-x402.ai, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-27).

Acts as a live x402 payment test counterparty, allowing developers to validate their payment stack with a real USDC settlement on Base.

## Facts

- Endpoint: GET https://gsc-x402.ai/api?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-27
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/gsc-x402-ai-payment-test-counterparty-dd9457b4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_HYbbIv3v1oViCp1P2ftBK

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 gsc-x402-ai-payment-test-counterparty-dd9457b4
```

Example prompt: Can you run a live end-to-end test of my x402 payment stack by hitting the gsc-x402.ai test counterparty with a real USDC settlement on Base, using a GET request?

## When to prefer this

Choose this endpoint when you need to validate an x402 payment implementation against a real, live counterparty that actually settles USDC on Base — not a mock or sandbox. It is the right choice for pre-production smoke tests, CI checks, and debugging payment middleware in an environment where a genuine financial transaction is required to confirm correctness.

## Known failure modes

- Insufficient USDC balance causes payment failure and a 402 response without settlement
- Malformed x402 payment header results in rejection
- Unsupported HTTP method (e.g. POST) returns an error since only GET, HEAD, DELETE are allowed
- Network issues on Base blockchain delay or fail settlement confirmation
- Missing or invalid wallet configuration prevents payment from being submitted

## How this service works

GSC's payment door — a real one-cent settlement on Base, signed receipt returned. Prove your agent's payment stack here.

## Output

A successful HTTP response confirming that the x402 payment challenge was met and a real $0.005 USDC payment was settled on Base, demonstrating that the caller's payment stack is functioning end to end.

## 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"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "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/gsc-x402-ai-payment-test-counterparty-dd9457b4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from gsc-x402.ai](https://www.zero.xyz/host/gsc-x402.ai/llms.txt)