# Fabler Labs URL Security Audit (x402 API)

> Fabler Labs URL Security Audit (x402 API) is a paid API for AI agents from x402.fablerlabs.com, paid per call via x402, $0.08/call, status unknown (last checked 2026-09-15).

Audits a public HTTPS URL for security issues by fetching its response metadata, checking headers, redirects, and reachability, then returning a pass/warn/block verdict.

## Facts

- Endpoint: GET https://x402.fablerlabs.com/audit/url-security
- Price: $0.08/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fabler-labs-url-security-audit-x402-api-d8b97c36
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_xVOATCwbu9B2qMxhf9zOC

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 fabler-labs-url-security-audit-x402-api-d8b97c36
```

Example prompt: Can you run a security audit on https://example.com and tell me if it passes, warns, or blocks — including any redirect hops and header issues?

## When to prefer this

Choose this endpoint when you need a lightweight, machine-payable ($0.08 USDC) security audit of a public HTTPS URL that returns a structured verdict with header analysis, redirect tracing, and reachability — without needing to set up your own web scanning infrastructure. Ideal for AI agents performing automated link safety checks, pre-flight URL validation, or developer header audits at low cost per call.

## Known failure modes

- URL is not reachable — reachable: false with null status
- URL uses a non-default port or includes credentials/fragments — input validation rejection
- Payment not included — 402 Payment Required with PAYMENT-REQUIRED header containing challenge
- URL resolves to a private/internal IP — blocked by scope restrictions
- Timeout fetching the target URL — may return reachable: false

## How this service works

Machine-payable endpoints for AI agents, over x402 protocol v2. Unpaid requests to a paid endpoint return `402 Payment Required` with an empty `{}` body and a typed challenge (price, network, asset, pay-to address) in a base64-encoded `PAYMENT-REQUIRED` response header; decode it, pay the USDC, and replay with a base64 `PAYMENT-SIGNATURE` header to get the result. Built and operated by an autonomous AI agent, filmed for transparency. Live status and prices are authoritative in https://fablerlabs.com/products.json.

## Output

A JSON object with a verdict (pass/warn/block), reachability boolean, final URL after redirects, the full redirect chain, HTTP response headers, an array of individual security checks with pass/warn/fail status, a summary count of passed/warned/failed checks, the HTTP status code, and the timestamp of the fetch. Scope is limited to public HTTPS response metadata only.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string",
       "format": "uri",
       "maxLength": 2048,
       "description": "Public HTTPS URL using the default port, with no credentials or fragment."
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fabler-labs-url-security-audit-x402-api-d8b97c36/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.fablerlabs.com](https://www.zero.xyz/host/x402.fablerlabs.com/llms.txt)