# Contract ABI Lookup via x402helper

> Contract ABI Lookup via x402helper is a paid API for AI agents from x402helper.xyz, paid per call via x402, $0.009/call, status unknown (last checked 2026-10-31).

Returns the ABI (Application Binary Interface) for a smart contract on an EVM-compatible network, given a contract address.

## Facts

- Endpoint: GET https://x402helper.xyz/89e509/contract/abi?utm_source=zero.xyz
- Price: $0.009/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/contract-abi-lookup-via-x402helper-45f957da
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_i-INhDls773PqpiaYJFpf

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 contract-abi-lookup-via-x402helper-45f957da
```

Example prompt: Can you fetch the ABI for the smart contract at 0x1234567890abcdef1234567890abcdef12345678 on the Base network?

## When to prefer this

Use this endpoint when you need to programmatically retrieve a smart contract's ABI from an EVM-compatible network (Base, Ethereum, Arbitrum, Optimism, Polygon, BNB) and are operating in an x402 micropayment-enabled agent environment. It is well-suited for agents that need to inspect contract interfaces before interacting with DeFi protocols or token contracts.

## Known failure modes

- Invalid or unverified contract address returns empty or null ABI
- Unsupported network name returns an error
- Contract not verified on-chain may return no ABI
- Malformed 0x address format causes validation failure
- Payment not included or insufficient USDC results in 402 rejection

## 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 contract ABI — an array of function signatures, event definitions, and constructor details for the requested smart contract on the specified EVM network.

## 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": [
      "address"
     ],
     "properties": {
      "address": {
       "type": "string",
       "default": null,
       "description": "Contract address, 0x + 40 hex"
      },
      "network": {
       "enum": [
        "base",
        "ethereum",
        "arbitrum",
        "optimism",
        "polygon",
        "bnb"
       ],
       "type": "string",
       "default": null,
       "description": "EVM network (default base)"
      }
     }
    }
   },
   "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/contract-abi-lookup-via-x402helper-45f957da/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)