# Forge Cascade Agent Payments x402 Demo

> Forge Cascade Agent Payments x402 Demo is a paid API for AI agents from api.relai.fi, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Returns a 402 Payment Required challenge to demonstrate the x402 HTTP payment protocol for AI agent micropayments.

## Facts

- Endpoint: POST https://api.relai.fi/relay/1781295889777/api/v1/agent-payments/x402-demo
- 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/forge-cascade-agent-payments-x402-demo-6c536d98
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_lliZZ07rGNQg7lYSpk9C1

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 forge-cascade-agent-payments-x402-demo-6c536d98 -d '<json body>'
```

Example prompt: Trigger the x402 payment challenge on the Forge Cascade demo endpoint so I can test whether my agent correctly handles a 402 Payment Required response and resolves it with a 0.01 USDC micropayment.

## When to prefer this

Use this endpoint when you need to test or demonstrate the x402 HTTP micropayment protocol flow, specifically to verify that an AI agent can correctly detect, parse, and respond to a 402 Payment Required challenge using USDC. Prefer this over building a mock yourself since it provides a real, live 402 challenge environment.

## Known failure modes

- Missing or malformed request body returns 400 Bad Request
- Network timeout if agent takes too long to respond
- Payment header already included may bypass challenge or return unexpected result
- Rate limiting may trigger 429 if called too frequently
- Incorrect content-type header may cause parsing errors

## How this service works

Public endpoint that intentionally returns a 402 challenge.

## Output

Returns an HTTP 402 Payment Required response containing an x402 challenge payload that specifies the payment amount (0.01 USDC), payment network, and instructions for the agent to fulfill the payment and retry the request.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/forge-cascade-agent-payments-x402-demo-6c536d98/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.relai.fi](https://www.zero.xyz/host/api.relai.fi/llms.txt)