# X402-BROKER Paywall Check

> X402-BROKER Paywall Check is a paid API for AI agents from mcp-gateway.agentdiet.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-22).

Checks whether a given HTTP URL is protected by an x402/L402 paywall and returns access status with compression ROI proof

## Facts

- Endpoint: GET https://mcp-gateway.agentdiet.dev/v1/paywall-check?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-22
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-broker-paywall-check-89a6650d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_q-o7IY8GKr5uvkosR9doL

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-broker-paywall-check-89a6650d
```

Example prompt: Can you check if the URL https://some-api.example.com/data is behind an x402 paywall — use a GET request and tell me whether it requires payment to access?

## When to prefer this

Use this endpoint when an AI agent needs to programmatically determine whether a target URL is protected by an x402, L402, or MPP paywall before committing to a payment flow. It is particularly useful in agentic workflows where an agent must decide dynamically whether to authorize a micropayment, and when the target could be any of 31,390+ MCP servers or x402 APIs in the broker's network. Prefer this over manual inspection or generic HTTP HEAD checks when you need structured paywall-presence confirmation plus ROI proof metadata.

## Known failure modes

- URL is unreachable or returns non-HTTP error — status will reflect failure
- URL is not x402/L402 protected — paywall check returns no gate detected
- Invalid or missing 'url' query parameter — request rejected with schema validation error
- Upstream endpoint rate-limits or blocks the probe request
- USDC payment on Base fails to settle — call not executed

## How this service works

Deterministic B2A/A2A/MCP/x402/MPP/L402 execution and intelligence node at https://mcp-gateway.agentdiet.dev settling in USDC on Base.

## Output

Returns a JSON object with a status field ('ok' or error), a data object with any retrieved content, and an roi_proof object containing a compression_ratio_pct value (e.g. 91.4) demonstrating the efficiency of the gateway's data handling.

## 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",
      "POST"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "url": {
       "type": "string"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {},
  "status": "ok",
  "roi_proof": {
   "compression_ratio_pct": 91.4
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-broker-paywall-check-89a6650d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from mcp-gateway.agentdiet.dev](https://www.zero.xyz/host/mcp-gateway.agentdiet.dev/llms.txt)