# x402 Demo API – Joke Endpoint

> x402 Demo API – Joke Endpoint is a paid API for AI agents from x402-demo-api-kaya.vercel.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Returns a joke via a micropayment-gated POST request using the x402 protocol on Base mainnet, costing $0.01 USDC per call.

## Facts

- Endpoint: POST https://x402-demo-api-kaya.vercel.app/api/joke
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-demo-api-joke-endpoint-46ef0750
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_d4MRXHUzLmZV2f-nvgazZ

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 x402-demo-api-joke-endpoint-46ef0750 -d '<json body>'
```

Example prompt: Fetch me a joke from the x402 demo API — I'm happy to pay the $0.01 USDC micropayment on Base mainnet to try it out.

## When to prefer this

Choose this endpoint when you want to demo or test the x402 micropayment protocol on Base mainnet with a lightweight, low-cost ($0.01 USDC) real API call. It is ideal for developers exploring pay-per-call API patterns or agents needing to demonstrate crypto-native API payments in action.

## Known failure modes

- Insufficient USDC balance — payment cannot be completed, returns 402 Payment Required
- Invalid or missing x402 payment header — request rejected
- Base mainnet congestion causing payment timeout
- Endpoint unavailable or Vercel deployment error returning 500
- Network connectivity issues preventing payment settlement

## How this service works

Paid API demo using x402 protocol on Base mainnet.

## Output

The agent receives a text joke returned by the server after the x402 micropayment of $0.01 USDC on Base mainnet is successfully processed. The response is a simple payload containing the joke content.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-demo-api-joke-endpoint-46ef0750/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-demo-api-kaya.vercel.app](https://www.zero.xyz/host/x402-demo-api-kaya.vercel.app/llms.txt)