# The Latent Lounge x402 Echo

> The Latent Lounge x402 Echo is a paid API for AI agents from www.thelatentlounge.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-12).

Returns a mirror of your x402 USDC payment details and settlement receipt headers for debugging x402 protocol integrations on Base mainnet.

## Facts

- Endpoint: GET https://www.thelatentlounge.com/api/x402/echo?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/the-latent-lounge-x402-echo-cab9f026
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_UUpL4V22YCVYz6nRH525I

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 the-latent-lounge-x402-echo-cab9f026
```

Example prompt: Send a real x402 USDC payment to the Latent Lounge echo endpoint on Base mainnet and show me everything it echoes back — the payer address, amount, header, nonce, validity window, and settlement receipt.

## When to prefer this

Choose this endpoint when you need to verify that your x402 client, wallet, or agent is correctly constructing and transmitting x402 payment headers on Base mainnet with real USDC. It is the canonical low-cost ($0.001) integration smoke-test for x402 — cheaper and faster than building a mock server, and it returns a real settlement receipt so you can confirm the full payment lifecycle works end-to-end.

## Known failure modes

- Missing or malformed x402 payment header returns 402 Payment Required
- Insufficient USDC balance causes payment failure before the endpoint is reached
- Wrong network (not Base mainnet) causes payment rejection
- Expired validity window in payment header causes rejection
- Invalid nonce or replayed nonce causes rejection

## How this service works

Test your x402 client for a tenth of a cent: a real USDC payment on Base mainnet that returns the payment you just made — x402 version, header, scheme, network, payer, amount, validity window and nonce — with the settlement receipt in the response headers. Built for debugging agents, wallets and x402 integrations.

## Output

A JSON object echoing the x402 payment just made, including x402Version (integer), header (string), scheme, network, payer address, amount in atomic USDC units (6 decimals), validity window, and nonce. The HTTP response headers also contain the settlement receipt confirming on-chain settlement.

## 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": {
     "type": "string",
     "const": "GET"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "type": "object",
     "properties": {
      "payer": {
       "type": "string"
      },
      "amount": {
       "type": "string",
       "description": "Atomic USDC units (6 decimals)."
      },
      "header": {
       "type": "string"
      },
      "network": {
       "type": "string"
      },
      "x402Version": {
       "type": "integer"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/the-latent-lounge-x402-echo-cab9f026/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from www.thelatentlounge.com](https://www.zero.xyz/host/www.thelatentlounge.com/llms.txt)