ERC-1155 balance

How many of one ERC-1155 token id an account holds, read straight from the contract. Send GET /api/chain/erc1155-balance with the required fields contract, address and tokenId and pay $0.002 per call over x402 or MPP (there is no free tier). It returns a JSON object with contract, address, tokenId, network and balance.

ERC-1155 is the multi-token standard behind most game items, editions and passes, where a single contract holds many ids and a balance is a quantity rather than ownership of one thing. Returns the balance as a decimal string. EVM chains: ethereum, base, polygon, arbitrum, optimism.

Category: Crypto & onchain data · Tags: evm erc1155 nft balance rpc · Also found as: 1155-balance multi-token-balance edition-balance

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Parameters

Example request

curl -i "https://agent402.tools/api/chain/erc1155-balance?contract=0x2953399124F0cBB46d2CbACD8A89cF0599974963&address=0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0&tokenId=1&network=polygon"

Without payment this returns HTTP 402 Payment Required with the exact price for chain-erc1155-balance; any x402 v2 or MPP client pays it and retries.

Example response

{
  "contract": "0x2953399124f0cbb46d2cbacd8a89cf0599974963",
  "address": "0xabf4fabd7c416fb67202e5f9002389fc75e2a9d0",
  "tokenId": "1",
  "network": "polygon",
  "balance": "0"
}

From an MCP client

catalog.call {
  "slug": "chain-erc1155-balance",
  "params": {
    "contract": "0x2953399124F0cBB46d2CbACD8A89cF0599974963",
    "address": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "tokenId": "1",
    "network": "polygon"
  }
}

The hosted connector at https://agent402.tools/mcp needs a payment for chain-erc1155-balance; the stdio package pays it from a wallet or from AGENT402_CREDITS_KEY. Local install: npx -y agent402-mcp.

Errors and behavior

• contract, address and tokenId are required. An input the tool rejects returns an HTTP 4xx whose body carries error, tool, expected, required and example, so the caller can correct it.
• A paid call that ends in any status of 400 or above is not charged over x402, MPP or a prepaid credits key: settlement is cancelled when the tool fails. The exception is a Tempo push credential, a transfer the buyer sent before the call: it settles before the tool runs, so if the tool then fails the payment is recorded as a refund owed to the paying wallet.
• Wallet-only: this tool reaches the network or stored state, so it has no proof-of-work tier. A prepaid card-credits key issued earlier (Authorization: Bearer a402_...) also pays it.
• A POST with a JSON body to /api/chain/erc1155-balance is served as this GET, with the body as the input.
• An Idempotency-Key header makes a retried paid call replay the first 200 instead of charging again (an answer larger than 1 MB is not replayed).

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();
client.setSpendControls?.(false); // keep your own spending ceiling in code
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/chain/erc1155-balance?contract=0x2953399124F0cBB46d2CbACD8A89cF0599974963&address=0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0&tokenId=1&network=polygon");

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