# Reliable JSON URL Preflight Check

> Reliable JSON URL Preflight Check is a paid API for AI agents from agent-json-reliability.onrender.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-01).

Performs a preflight check on a URL before fetching it for JSON repair or validation processing

## Facts

- Endpoint: POST https://agent-json-reliability.onrender.com/v1/url/preflight?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/reliable-json-url-preflight-check-8367af88
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_j0jnBWxq9itUYUZ3GgkSb

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 reliable-json-url-preflight-check-8367af88 -d '<json body>'
```

Example prompt: Before we start repairing the JSON from https://api.example.com/data/results.json, can you do a preflight check on that URL to make sure it's reachable and ready for processing?

## When to prefer this

Use this endpoint as a first step in any JSON repair or validation workflow when the JSON source is a remote URL rather than an inline payload. It's the right choice when you want to fail fast before paying for a repair call, when debugging connectivity issues with a JSON data source, or when building a robust agent pipeline that needs to confirm URL availability before proceeding.

## Known failure modes

- URL is unreachable or times out — ok: false returned
- Malformed URL input — request rejected
- URL points to non-JSON content — may still pass preflight but fail in later steps
- Rate limiting or upstream connectivity issues on the render.com host
- Payment not completed for paid endpoints — 402 response

## How this service works

Deterministic JSON repair and JSON Schema validation for AI agents. Free MCP, inspect, validate, repair. Paid POST /v1/json/reliable 0.003 USDC via x402 on Base.

## Output

Returns a simple JSON object with an 'ok' boolean indicating whether the URL passed the preflight check and is accessible for subsequent JSON repair or validation operations.

## Response schema (JSON Schema)

```json
{
 "example": {
  "ok": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/reliable-json-url-preflight-check-8367af88/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent-json-reliability.onrender.com](https://www.zero.xyz/host/agent-json-reliability.onrender.com/llms.txt)