# AEML x402 Tier 2 Payment Receipt

> AEML x402 Tier 2 Payment Receipt is a paid API for AI agents from aeml-x402.zeabur.app, paid per call via x402, $0.03/call, status unknown (last checked 2026-09-13).

Accepts an x402 USDC-on-Base micropayment and returns a short-lived signed receipt for tier 2 access, verifiable by gauge-frontdesk /pay/verify.

## Facts

- Endpoint: GET https://aeml-x402.zeabur.app/pay/tier2
- Price: $0.03/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/aeml-x402-tier-2-payment-receipt-57e818d5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_AQVeWgK6b6vhiYdXIDbex

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 aeml-x402-tier-2-payment-receipt-57e818d5
```

Example prompt: Pay the tier 2 x402 gate using USDC on Base and get me back the signed receipt so I can verify access with gauge-frontdesk.

## When to prefer this

Use this endpoint when you need to gate tier 2 access using the x402 USDC-on-Base micropayment protocol and require a short-lived signed receipt for subsequent verification by gauge-frontdesk /pay/verify. Prefer this over tier 1 when the downstream service requires tier 2 authorization level.

## Known failure modes

- Payment not detected or insufficient USDC — returns 402 Payment Required with x402 payment instructions
- Expired or replayed payment header — rejected with auth error
- Invalid x402 payment format — bad request error
- Network congestion on Base causing payment confirmation delays
- Receipt already consumed or expired before verification

## How this service works

Tiered payment receipt (tier 2): pay once with x402 and get back a short-lived receipt token that /pay/verify checks for you. The tier is fixed by the path - you do not send it. Optional ?ref= carries your own opaque reference, such as a query hash, straight through to the receipt. This mints a receipt rather than returning data, so there is no lookup that can come back empty.

## Output

Returns a JSON object with: ok (boolean indicating success), exp (Unix timestamp when receipt expires), ref (optional query hash echo), tier (integer, should be 2), receipt (signed receipt string for downstream verification), and paid_via (payment method string indicating x402/USDC/Base).

## Request schema (JSON Schema)

```json
{
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "type": {
     "const": "http"
    },
    "method": {
     "type": "string",
     "enum": [
      "GET"
     ]
    },
    "queryParams": {
     "type": "object",
     "additionalProperties": false,
     "properties": {
      "tier": {
       "type": "string",
       "description": "optional - ignored; fixed to 2 by this path"
      },
      "ref": {
       "type": "string",
       "description": "optional - opaque reference such as a query hash"
      }
     }
    }
   },
   "required": [
    "type",
    "method"
   ]
  },
  "output": {
   "type": "object",
   "properties": {
    "type": {
     "const": "json"
    }
   },
   "required": [
    "type"
   ]
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/aeml-x402-tier-2-payment-receipt-57e818d5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from aeml-x402.zeabur.app](https://www.zero.xyz/host/aeml-x402.zeabur.app/llms.txt)