# x402helper.xyz Yield Protocol Preview

> x402helper.xyz Yield Protocol Preview is a paid API for AI agents from x402helper.xyz, paid per call via x402, $0.013/call, status unknown (last checked 2026-10-31).

Returns a preview of a yield protocol transaction (deposit or redeem) for Aave v3, Compound v3, or any ERC-4626 vault on Base, paid via x402 USDC micropayment.

## Facts

- Endpoint: GET https://x402helper.xyz/89e509/yield/preview?utm_source=zero.xyz
- Price: $0.013/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402helper-xyz-yield-protocol-preview-be8e0c58
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_os6yLWGUhZcrbvFRb5-ON

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 x402helper-xyz-yield-protocol-preview-be8e0c58
```

Example prompt: Can you preview what I'd get for depositing 1000000 USDC (in atomic units) into Aave v3 using the deposit action, so I can check the transaction before I commit?

## When to prefer this

Use this endpoint when you need to simulate or preview a DeFi yield protocol transaction (Aave v3, Compound v3, or any Base ERC-4626 vault) before executing it on-chain. It is the right choice when the agent needs computed transaction details without side effects, and is willing to pay a $0.013 USDC x402 micropayment per call.

## Known failure modes

- Missing required 'protocol' or 'amount' query parameters returns an error
- Invalid or unsupported asset symbol for the chosen protocol
- Vault address not found or not a valid ERC-4626 contract on Base
- OFAC screening failure blocks the request
- x402 payment not attached or insufficient USDC causes 402 response
- Network or on-chain RPC failure when resolving vault data

## How this service works

X402 micropayments server — AI agents pay USDC for OFAC screening, rates, and billing verification.

## Output

A JSON object with a 'success' boolean and a 'result' object containing the computed preview details of the requested yield protocol operation (deposit or redeem), including expected amounts and transaction parameters.

## 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": [
      "protocol",
      "amount"
     ],
     "properties": {
      "asset": {
       "type": "string",
       "default": null,
       "description": "For aave-v3/compound-v3: the asset symbol (USDC, WETH, ...) or a 0x ERC-20 address. Compound III earns only on its base asset."
      },
      "vault": {
       "type": "string",
       "default": null,
       "description": "For erc4626: the vault 0x address (ANY Base ERC-4626) or a seed slug. Resolved on-chain."
      },
      "action": {
       "enum": [
        "deposit",
        "redeem"
       ],
       "type": "string",
       "default": null,
       "description": "deposit (supply) or redeem (withdraw). Default deposit."
      },
      "amount": {
       "type": "string",
       "default": null,
       "description": "Raw atomic units. deposit: underlying assets. redeem: aave/comet = underlying (or 'max'); erc4626 = shares (or 'max')."
      },
      "protocol": {
       "enum": [
        "aave-v3",
        "compound-v3",
        "erc4626"
       ],
       "type": "string",
       "default": null,
       "description": "Yield protocol: aave-v3, compound-v3 or erc4626."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {},
  "success": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402helper-xyz-yield-protocol-preview-be8e0c58/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402helper.xyz](https://www.zero.xyz/host/x402helper.xyz/llms.txt)