Verified contract ABI (Sourcify)

Fetch the verified ABI for a contract address from Sourcify, plus a ready-to-use list of human-readable function signatures with their 4-byte selectors. Covers 8 EVM mainnets. Unverified contracts return a structured {verified:false} miss. Pair with /api/calldata-decode to decode transactions against this ABI.

Input

Example output

{
  "address": "0x833589fcd6edb6e08f4c7c32d4f71b54bda02913",
  "network": "base",
  "chainId": 8453,
  "verified": true,
  "match": "exact_match",
  "abi": [
    {
      "name": "implementation",
      "type": "function",
      "inputs": [],
      "outputs": [
        {
          "type": "address"
        }
      ]
    }
  ],
  "functions": [
    {
      "signature": "implementation()",
      "selector": "0x5c60da1b"
    }
  ],
  "events": [
    {
      "signature": "Upgraded(address)"
    }
  ]
}

Try it — see the 402 challenge (free)

curl -i -X POST https://agent402.tools/api/contract-abi \
  -H "Content-Type: application/json" \
  -d '{"address":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","network":"base"}'

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/contract-abi", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "network": "base"
  }),
});

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