# x402 Trust Layer — Pre-x402 Alchemy Guard

> x402 Trust Layer — Pre-x402 Alchemy Guard is a paid API for AI agents from x402trustlayer.xyz, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-03).

Pre-flight guard check that validates whether a GET, HEAD, or DELETE HTTP request is allowed under x402 trust infrastructure before payment settlement proceeds.

## Facts

- Endpoint: POST https://x402trustlayer.xyz/api/guard/pre-x402-alchemy?utm_source=zero.xyz
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-03
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-trust-layer-pre-x402-alchemy-guard-f6d0dff8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_9n_Ep0IeaX8HEvxTMyRF9

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-trust-layer-pre-x402-alchemy-guard-f6d0dff8 -d '<json body>'
```

Example prompt: Before I pay to call that x402-protected API endpoint, run a pre-flight guard check on my GET request using the x402 Alchemy guard to confirm it's allowed under the trust layer.

## When to prefer this

Use this endpoint when you need to perform a pre-flight authorization check on a read-type HTTP request (GET, HEAD, or DELETE) before committing to an x402 micropayment. It is specifically designed for the x402 trust infrastructure's Alchemy integration and is the right choice when you want to validate whether a request will be permitted before incurring payment costs.

## Known failure modes

- Invalid method supplied (only GET, HEAD, DELETE accepted) — likely 400 or validation error
- Missing required 'type' or 'method' fields in input object — schema validation failure
- Request blocked by guard rules — returns allowed: false with explanatory summary
- Payment not settled or insufficient USDC — x402 payment required error
- Network or upstream Alchemy integration failure — service unavailable response

## How this service works

68 paid x402 trust infrastructure APIs: guard, semantic escrow, mandate diff, certified seller network, KYM, mandates, compliance, disputes, and orchestration.

## Output

Returns a JSON object with three fields: 'ok' (boolean indicating the call succeeded), 'allowed' (boolean indicating whether the request is permitted to proceed), and 'summary' (a human-readable explanation of the guard decision). Example: {ok: true, allowed: true, summary: 'Paid response after x402 settlement'}.

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "ok",
      "allowed",
      "summary"
     ],
     "properties": {
      "ok": {
       "type": "boolean"
      },
      "allowed": {
       "type": "boolean"
      },
      "summary": {
       "type": "string"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "allowed": true,
  "summary": "Paid response after x402 settlement"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-trust-layer-pre-x402-alchemy-guard-f6d0dff8/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402trustlayer.xyz](https://www.zero.xyz/host/x402trustlayer.xyz/llms.txt)