Quickstart: Deploy a Smart Contract using Bytecode

Circle Contracts provides an API for deploying, exploring, and interacting with smart contracts. The platform offers a powerful toolset for developers to build decentralized applications and for businesses to transition to web3.

This guide can also be followed to deploy smart contracts on the Ethereum network by changing the blockchain parameter in your request. Additionally, you can deploy to Mainnet by swapping out the Testnet API key for a Mainnet API key. See the Testnet vs Mainnet guide for more details.

Part One: Fund Your Wallet with Gas

If you already have a Circle developer-controlled wallet on Polygon Amoy with Testnet MATIC, proceed to part two. If you haven’t created a developer-controlled wallet, head to our quickstart Create Your First Developer-Controlled Wallet guide. Once completed, jump into steps one and two below to acquire gas for deploying your first contract.

1. Acquire Tokens for Gas Fees

In Web3, gas fees refers to transaction fees that are always paid in the native currency of the blockchain network. For example, to deploy a contract on a contract on the Ethereum network, you must pay the transaction fee in Ether (ETH). Similarly, on the Polygon network, the fee would be in MATIC. To ensure smooth transactions, it is important to have a sufficient amount of the native token in your wallet.

To gather tokens for gas, we recommend using the Polygon Faucet. When you visit the faucet’s website, you will be prompted to provide your wallet’s address. To acquire it, make a request to GET /wallets as shown below noting down Wallet One’s address wallets[0].address.

Node.js SDK

// Import and configure the developer-controlled wallet SDK
const {
  initiateDeveloperControlledWalletsClient,
} = require("@circle-fin/developer-controlled-wallets");
const circleDeveloperSdk = initiateDeveloperControlledWalletsClient({
  apiKey: "<API_KEY>",
  entitySecret: "<ENTITY_SECRET>",
});

// Import and configure the smart contract SDK
const {
  initiateSmartContractPlatformClient,
} = require("@circle-fin/smart-contract-platform");
const circleContractSdk = initiateSmartContractPlatformClient({
  apiKey: "<API_KEY>",
  entitySecret: "<ENTITY_SECRET>",
});

const response = await circleDeveloperSdk.listWallets({
  blockchain: "MATIC-AMOY",
});

Response Body

{
  "data": {
    "wallets": [
      {
        "id": "17c411ba-7aef-4c5d-a4f8-951a60ce7fb1",
        "state": "LIVE",
        "walletSetId": "018b42d3-8934-7ad5-8ec7-a34179a7e6e5",
        "custodyType": "DEVELOPER",
        "address": "0x09e768def76316d8f127efb73047a046598fef7b",
        "blockchain": "MATIC-AMOY",
        "accountType": "EOA",
        "updateDate": "2023-10-18T12:48:45Z",
        "createDate": "2023-10-18T12:48:45Z"
      },
      {
        "id": "8172d817-32b5-4f52-b071-4a8d789e08fc",
        "state": "LIVE",
        "walletSetId": "018b42d3-8934-7ad5-8ec7-a34179a7e6e5",
        "custodyType": "DEVELOPER",
        "address": "0x48f2d63f13f62ff1e3ab9dbda56f3e5c531557b2",
        "blockchain": "MATIC-AMOY",
        "accountType": "EOA",
        "updateDate": "2023-10-18T12:48:45Z",
        "createDate": "2023-10-18T12:48:45Z"
      }
    ]
  }
}

2. Check the Wallet’s Balance

Before deploying the contract, double-check the MATIC tokens were received. This can be done by making a request to GET /wallets/{id}/balances providing the ID of Wallet One from the previous step.

Node.js SDK

const response = await circleDeveloperSdk.getWalletTokenBalance({
  id: "17c411ba-7aef-4c5d-a4f8-951a60ce7fb1",
});

Response Body

{
  "data": {
    "tokenBalances": [
      {
        "token": {
          "id": "e4f549f9-a910-59b1-b5cd-8f972871f5db",
          "blockchain": "MATIC-AMOY",
          "name": "Polygon-Amoy",
          "symbol": "MATIC-AMOY",
          "decimals": 18,
          "isNative": true,
          "updateDate": "2023-06-29T02:37:14Z",
          "createDate": "2023-06-29T02:37:14Z"
        },
        "amount": "0.2",
        "updateDate": "2023-08-03T22:22:07Z"
      }
    ]
  }
}

Part Two: Write and Deploy Smart Contract

3. Writing the Smart Contract

OpenZeppelin

This tutorial will use OpenZeppelin’s Contract Wizard to generate an ERC-721 smart contract. OpenZeppelin offers a secure smart contract development library - built on top of a foundation of community-vetted code.

The Contract Wizard includes:

1. Implementations of standards like ERC-20 and ERC-721.
2. Flexible role-based permissions scheme.
3. Reusable Solidity components to build custom contracts and complex decentralized systems.

In the OpenZeppelin Contract Wizard

1. Select the ERC-721 template and the additional features you want to add to your contract.
2. Select Mintable. By default, this selects the Ownable access control, restricting the safeMint function to the wallet owner.

3. Select Open in Remix button to create a new workspace in Remix and compile the contract.

4. Select Compile contract to compile the Solidity code into bytecode for the Ethereum Virtual Machine (EVM). We recommend using the default compiler settings which are appropriate for most use cases.

   1. In Remix, you don’t need to update the code at all.
   2. If you don’t see compile contract, ensure you are in the Solidity Compiler section. If not, select it in the left-hand navigation bar.

5. Once the compilation is complete, note down the ABI and bytecode. These values will be used in the next step.
   1. The compiler output is available under Compilation Details. For more information on the Solidity compiler’s outputs, see using the compiler.
   2. The Application Binary Interface (ABI) is the standard way to interact with contracts on an EVM from outside the blockchain and for contract-to-contract interaction.

4. Deploy the Smart Contract

To deploy a smart contract, we will use the POST /contracts/deploy method. In the request body, you will provide the following values gathered from the prior steps:

1. entitySecretCiphertext uniquely generated Entity Secret Ciphertext. To learn more about generating the ciphertext for this request, see the guide How to Re-Encrypt the Entity Secret.
2. walletId acquired from step 1. This is the identifier of your wallet on a specific blockchain.
3. abiJSON acquired from the Solidity compiler in step 3.
4. bytecode acquired from the Solidity compiler in step 3.
5. constructorParameters the address to set as the initial owner of the contract. For this guide, it should be the address of your wallet, but it can be any address.

Common Syntax Errors

• abiJSON must be stringified i.e. quote escaped. To stringfy the JSON you can use the JsonFormatter’s Stringfy tool.
• bytecode must be prefixed with 0x.

Node.js SDK

const response = await circleContractSdk.deployContract({
  name: "First Contract Name",
  description: "First Contract Description",
  walletId: "046b6c7f-0b8a-43b9-b35d-6489e6daee91",
  blockchain: "MATIC-AMOY",
  fee: {
    type: "level",
    config: {
      feeLevel: "MEDIUM",
    },
  },
  constructorParameters: ["0x6F77e56DFA40190349E1078e97ac3Eb479E0Dac6"],
  entitySecretCiphertext: "0NtD3d3+nmgb4GqYQXzAjKF8h5Zq6sHM2k/...",
  abiJSON:
    '[\n\t{\n\t\t"inputs": [],\n\t\t"stateMutability": "nonpayable",\n\t\t"type": "constructor"\n\t},\n\t{\n\t\t"anonymous": false,',
  bytecode: "0x...",
});

If the call is successful, you will receive a transactionId and a contractId in the response.

Response Body

{
  "data": {
    "contractId": "0189db12-4089-72eb-b4a8-2aee38cc38fe",
    "transactionId": "7b989c65-9678-56d8-a998-d295b8b04535"
  }
}

You can now call GET /contracts/{id} to check the status of your transaction. When the transaction has been confirmed on-chain, the contract response object will contain the contractAddress and have a status of PENDING. After 12 block confirmations, the contract will have a status of COMPLETE - as seen below.

Node.js SDK

const response = await circleContractSdk.getContract({
  id: "0189db84-72b7-7fcc-832b-5bf886b9a0ef",
});

JSON

{
  "data": {
    "contract": {
      "id": "0189db84-72b7-7fcc-832b-5bf886b9a0ef",
      "deploymentTransactionId": "4f5bfa38-c598-56a6-932e-8b5bbd3d5fc9",
      "name": "First Contract Name",
      "description": "First Contract Description",
      "contractInputType": "BYTECODE",
      "createDate": "2023-08-09T18:17:17Z",
      "updateDate": "2023-08-09T18:17:17Z",
      "archived": false,
      "contractAddress": "0x1e124d7384cd34448ea5907bd0052a79355ab5eb",
      "blockchain": "MATIC-AMOY",
      "status": "COMPLETE",
      "deployerAddress": "0x1bf9ad0cc2ad298c69a2995aa806ee832788218c",
      "txHash": "0x241c4df6f08f9ed2b569c9f9b1cc48fb6074ffffaeee7552e716ce059161a743",
      "abiJSON": "[\n\t{\n\t\t\"inputs\": [],\n\t\t\"stateMutability\": \"nonpayable\",\n\t\t\"type\": \"constructor\"\n\t},\n\t{\n\t\t\"anonymous\": false,",
      "functions": [
        {
          "name": "approve",
          "type": "function",
          "inputs": [
            {
              "name": "to",
              "type": "address"
            },
            {
              "name": "tokenId",
              "type": "uint256"
            }
          ],
          "stateMutability": "nonpayable"
        }
      ],
      "verificationStatus": "UNVERIFIED"
    }
  }
}

If you have configured Webhooks, you will receive notifications on the status of the deployment transaction. Additionally, you can view your deployed contract on the Polygon Amoy block explorer Polygonscan by running a search using contractAddress.