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Contracts

Call or deploy contracts from your backend wallet to any EVM blockchain with one API call.

Write to a contract

This request requires gas funds in the backend wallet.

const resp = await fetch(
  "<engine_url>/contract/<chain>/<contract_address>/write",
  {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      Authorization: "Bearer <access_token>",
      "x-backend-wallet-address": "<backend_wallet_address>",
    },
    body: JSON.stringify({
      functionName: "transferFrom",
      args: [
        "0x1946267d81Fb8aDeeEa28e6B98bcD446c8248473",
        "0x3EcDBF3B911d0e9052b64850693888b008e18373",
        "0",
      ],
    }),
  },
);
 
const { result } = await resp.json();
// queueId is a reference to the transaction queued by Engine.
console.log("Queue ID:", result.queueId);

See API reference

Call a payable method

To send native tokens to a payable method (e.g. ETH on Ethereum), set txOverrides.value in the request body to POST /contract/<chain>/<contract_address>/write.

{
  functionName: "...",
  args: [ ... ],
  txOverrides: {
    value: 1000000000000000, // 0.001 ETH in wei
  }
}

Override gas settings

Coming soon.

To override the estimated gas settings for your transaction, set txOverrides.gasLimit and txOverrides.gasPrice in the request body to POST /contract/<chain>/<contract_address>/write.

{
  functionName: "...",
  args: [ ... ],
  txOverrides: {
    gasLimit: 150000,
    gasPrice: 22000000000, // 22 gwei in wei
  }
}

Read from a contract

const resp = await fetch(
  "<engine_url>/contract/<chain>/<contract_address>/read?functionName=balanceOf&args=0x3EcDBF3B911d0e9052b64850693888b008e18373",
  {
    headers: {
      Authorization: "Bearer <access_token>",
    },
  },
);
 
const { result } = await resp.json();
console.log("ERC-20 balance:", result);

Deploy a contract

This request requires gas funds in the backend wallet.

const resp = await fetch(
  "<engine_url>/deploy/<chain>/prebuilts/nft-drop",
  {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      Authorization: "Bearer <access_token>",
      "x-backend-wallet-address": "<backend_wallet_address>",
    },
    body: JSON.stringify({
      contractMetadata: {
        name: "thirdweb Engine example",
        symbol: "eng",
        primary_sale_recipient:
          "0x3EcDBF3B911d0e9052b64850693888b008e18373",
      },
    }),
  },
);
 
const { result } = await resp.json();
// queueId is a reference to the transaction queued by Engine.
console.log("Queue ID:", result.queueId);