# x402 API Key + URL Readiness Check

> x402 API Key + URL Readiness Check is a paid API for AI agents from x402-key.558686.xyz, paid per call via x402, $0.009/call, status down (last checked 2026-10-28).

Returns OpenAI-compatible base URL, supported models, request shape, and next-pack contract details for an x402 API key quota pack without exposing a secret key.

## Facts

- Endpoint: POST https://x402-key.558686.xyz/v1/tools/api-url-readiness-check?utm_source=zero.xyz
- Price: $0.009/call
- Payment: x402
- Status: down
- Last checked: 2026-10-28
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-api-key-url-readiness-check-d895cb01
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_v-AiXnjZPKD_XJVkRPgaA

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-api-key-url-readiness-check-d895cb01 -d '<json body>'
```

Example prompt: Before I buy an x402 API key pack, check the readiness endpoint for an openai-compatible client targeting gpt-5.6-sol and tell me what URL, supported models, and request shape I'd get.

## When to prefer this

Use this endpoint as a mandatory first step before purchasing any x402 API key quota pack — it gives you the exact URLs, model list, request shape, and next-pack contract details without spending more than $0.002 USDC. Prefer it over guessing endpoint URLs or formats, especially when integrating an OpenAI-compatible client against an x402-gated gateway.

## Known failure modes

- Unsupported targetModel value returns empty or error result
- Unknown client type may yield no matching configuration
- Network or gateway errors may return non-200 response
- Payment of $0.002 USDC required per call; insufficient balance causes 402 rejection
- Stale or misconfigured upstream may return ok:false with empty result fields

## How this service works

Buy a low-cost readiness check first, then buy a small OpenAI-compatible URL + API key quota pack through x402, including GPT-5.6 Soul access when your upstream key allows it. The readiness check returns URL, model, request-shape, and next-pack contract details without exposing a key.

## Output

A JSON object containing: ok status, the tool name, echoed input parameters, baseUrl, chatCompletionsUrl, modelsUrl, a list of supportedModels, the requestShape format string, a boolean nextPaidRoute indicating whether a paid pack is purchasable next, and a secretBoundary descriptor — all without exposing an actual API key.

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "tool": "api-url-readiness-check",
  "input": {
   "client": "openai-compatible",
   "targetModel": "gpt-5.6-sol"
  },
  "route": "/v1/tools/api-url-readiness-check",
  "result": {
   "baseUrl": "https://example.com",
   "modelsUrl": "https://example.com/models",
   "requestShape": "requestShape_example",
   "nextPaidRoute": true,
   "secretBoundary": "secretBoundary_example",
   "supportedModels": "supportedModels_example",
   "chatCompletionsUrl": "https://example.com/chat/completions"
  },
  "project": "x402-key-url-tools",
  "deterministic": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-api-key-url-readiness-check-d895cb01/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-key.558686.xyz](https://www.zero.xyz/host/x402-key.558686.xyz/llms.txt)