# Contract ABI Lookup by Address and Chain

> Contract ABI Lookup by Address and Chain is a paid API for AI agents from api.x402node.dev, paid per call via x402, $0.018/call, status unknown (last checked 2026-09-15).

Fetches and parses the verified ABI for a smart contract by address and chain, returning function signatures, event names, and full decoded JSON ABI.

## Facts

- Endpoint: GET https://api.x402node.dev/contract/abi
- Price: $0.018/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/contract-abi-lookup-by-address-and-chain-5d42988e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_TR8sl2LJF7eF9OzbiXq3f

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-by-address-and-chain-5d42988e
```

Example prompt: Can you pull the verified ABI for the Uniswap V3 router contract at 0xE592427A0AEce92De3Edee1F18E0157C05861564 on Ethereum mainnet (chain ID 1)? I need the full function and event list so I can figure out how to call it.

## When to prefer this

Use this endpoint when you need the verified ABI for a specific smart contract to encode function calls, decode transaction data, or inspect available methods and events. Prefer this over manual ABI guessing or generic tools when you have a contract address and need authoritative, parsed ABI data backed by a block explorer.

## Known failure modes

- Contract address not verified on the block explorer — returns error or empty ABI
- Unsupported chain ID — returns error indicating chain not available
- Invalid contract address format — returns validation error
- Block explorer API key rate limit hit — returns upstream error
- Contract is a proxy and ABI reflects proxy not implementation — may return incomplete interface

## How this service works

Verified contract ABI by address and chain, returned as parsed JSON plus function and event name lists, from a block explorer behind an API key. Lets an agent decode and interact with a contract. contract abi, get abi, decode contract, function signatures, smart contract interface

## Output

Returns the full verified contract ABI as parsed JSON, along with a list of function names and their signatures (including parameter types) and a list of event names emitted by the contract — everything needed to encode calls or decode logs.

## 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": {
      "chain": {
       "type": "string",
       "description": "ethereum, base, arbitrum, optimism, polygon, bsc (default ethereum)"
      },
      "address": {
       "type": "string",
       "description": "contract 0x..."
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/contract-abi-lookup-by-address-and-chain-5d42988e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.x402node.dev](https://www.zero.xyz/host/api.x402node.dev/llms.txt)