# KEVAREMESH x402 Challenge Decode

> KEVAREMESH x402 Challenge Decode is a paid API for AI agents from kevaremesh-web.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-25).

Decodes and inspects an x402 HTTP 402 Payment Required challenge header to reveal payment terms, asset, network, and recipient — without signing or submitting any payment.

## Facts

- Endpoint: POST https://kevaremesh-web.vercel.app/api/x402/x402-challenge-decode?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-25
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/kevaremesh-x402-challenge-decode-245678fa
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_o2J4O8YKMvv8O5MoawpBV

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 kevaremesh-x402-challenge-decode-245678fa -d '<json body>'
```

Example prompt: I just got a 402 Payment Required response from an API — can you decode the payment_required challenge string for me so I can see what asset, amount, and wallet address it's asking for before I decide to pay?

## When to prefer this

Use this endpoint when an AI agent or procurement system needs to inspect x402 payment terms safely before deciding whether to authorize a payment — it is purely read-only and guarantees no funds are moved. Prefer it over raw HTTP parsing when you need structured access to the payTo address, asset, network, and amount from a 402 challenge in a single call.

## Known failure modes

- Malformed or non-x402 payment_required string returns an error field in the result object
- Empty or missing payment_required field results in a decode error
- Payload exceeding 131072 character limit may be rejected
- Unsupported x402 version may produce incomplete field extraction

## How this service works

Buyer-first MCP procurement gateway that discovers, compares and routes live x402 APIs without making the buyer choose a provider.

## Output

A JSON object containing the fully decoded x402 challenge: the list of accepted payment options (each with asset, payTo address, amount, scheme, network, and maxTimeoutSeconds), the protected resource URL, the x402 version number, whether extensions are present, a count of accepted payment methods, and a safety attestation confirming no funds were moved, no payment was signed, and no network payment request was made.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "payment_required": {
   "type": "string",
   "maxLength": 131072
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "error": "Payment required",
   "safety": {
    "funds_moved": false,
    "decoded_only": true,
    "payment_signed": false,
    "network_request": false
   },
   "accepts": [
    {
     "asset": "USDC",
     "payTo": "0x0000000000000000000000000000000000000000",
     "amount": "1000",
     "scheme": "exact",
     "network": "eip155:8453",
     "maxTimeoutSeconds": 60
    }
   ],
   "resource": {
    "url": "https://merchant.example/api"
   },
   "accept_count": 1,
   "x402_version": 2,
   "extensions_present": false
  },
  "product": "kevaremesh_x402_challenge_decode_v2",
  "service": "KEVAREMESH",
  "tool_name": "kevaremesh_x402_challenge_decode",
  "limitations": [
   "Decode/inspect only; never signs or submits payment"
  ],
  "generated_at": "2026-09-18T00:00:00.000Z"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/kevaremesh-x402-challenge-decode-245678fa/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from kevaremesh-web.vercel.app](https://www.zero.xyz/host/kevaremesh-web.vercel.app/llms.txt)