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Truffle quickstart

This page will take you through the basics of creating a Truffle project and deploying a smart contract to a blockchain.

Note: Before you begin, ensure that you've read the official Ethereum documentation.

Install Truffle

Before you can use Truffle, install it using the npm command. Refer to the installation instructions to install Truffle.

Create a project

You need to run most Truffle commands against an existing Truffle project. So the first step is to create a Truffle project.

You can create a bare project without smart contracts using truffle init, but for those getting started, you can use Truffle Boxes, which are example applications and project templates. We'll use the MetaCoin box, which creates a token that can be transferred between accounts. Note that this is not ERC-20 compatible.

  1. Download ("unbox") the MetaCoin box:
truffle unbox metacoin [PATH/TO/DIRECTORY]

Once this operation is completed, you'll now have a project structure with the following items:

Explore the project

Note: This page is just a quickstart, so we're not going to go into much detail here. We'll be going over building a truffle project from the command line. All of these commands can be executed through our VS Code extension as well!

  1. Open the contracts/MetaCoin.sol file in a text editor. This is a smart contract (written in Solidity) that creates a MetaCoin token. Note that this also references another Solidity file contracts/ConvertLib.sol in the same directory.

  2. Open the migrations/1_deploy_contracts.js file. This file is the migration (deployment) script.

  3. Open the test/TestMetaCoin.sol file. This is a test file written in Solidity which ensures that your contract is working as expected.

  4. Open the test/metacoin.js file. This is a test file written in JavaScript which performs a similar function to the Solidity test above. The box does not include one, but Truffle tests can also be written in typescript.

  5. Open the truffle-config.js file. This is the Truffle configuration file, for setting network information and other project-related settings. The file is blank, but this is okay, as we'll be using a Truffle command that has some defaults built-in.

Test

To run all tests, you can simply run truffle test. Because development is commented out in truffle-config.js, truffle test will spin up and tear down a local test instance (ganache). If you want to use more of ganache's features, you can spin up a separate instance and specify the port number in the truffle-config.

TestMetaCoin
  ✔ testInitialBalanceUsingDeployedContract
  ✔ testInitialBalanceWithNewMetaCoin

Contract: MetaCoin
  ✔ should put 10000 MetaCoin in the first account
  ✔ should call a function that depends on a linked library
  ✔ should send coin correctly (52ms)

You can also run each test individually by calling truffle test ./test/TestMetaCoin.sol and truffle test ./test/metacoin.js.

Note: If you're on Windows and encountering problems running this command, please see the documentation on resolving naming conflicts on Windows.

These two tests were run against the contract, with descriptions displayed on what the tests are supposed to do.

If you're running into any issues, try out our Truffle debugger!

Compile

If you want to only compile, you can simply run truffle compile.

You will see the following output:

Compiling your contracts...
===========================
> Compiling ./contracts/ConvertLib.sol
> Compiling ./contracts/MetaCoin.sol
> Artifacts written to /Users/emilylin/dev/metacoin-box/build/contracts
> Compiled successfully using:
- solc: 0.8.13+commit.abaa5c0e.Emscripten.clang

Migrate with Truffle Develop

Note: To use a separate Ganache instance, please skip to the next section.

To deploy our smart contracts, we're going to need to connect to a blockchain. Truffle has a built-in personal blockchain that can be used for testing. This blockchain is local to your system and does not interact with the main Ethereum network.

You can create this blockchain and interact with it using Truffle Develop.

  1. Run Truffle Develop:
truffle develop

You will see the following information:

Truffle Develop started at http://127.0.0.1:9545/

Accounts:
(0) 0x627306090abab3a6e1400e9345bc60c78a8bef57
(1) 0xf17f52151ebef6c7334fad080c5704d77216b732
(2) 0xc5fdf4076b8f3a5357c5e395ab970b5b54098fef
(3) 0x821aea9a577a9b44299b9c15c88cf3087f3b5544
(4) 0x0d1d4e623d10f9fba5db95830f7d3839406c6af2
(5) 0x2932b7a2355d6fecc4b5c0b6bd44cc31df247a2e
(6) 0x2191ef87e392377ec08e7c08eb105ef5448eced5
(7) 0x0f4f2ac550a1b4e2280d04c21cea7ebd822934b5
(8) 0x6330a553fc93768f612722bb8c2ec78ac90b3bbc
(9) 0x5aeda56215b167893e80b4fe645ba6d5bab767de

Private Keys:
(0) c87509a1c067bbde78beb793e6fa76530b6382a4c0241e5e4a9ec0a0f44dc0d3
(1) ae6ae8e5ccbfb04590405997ee2d52d2b330726137b875053c36d94e974d162f
(2) 0dbbe8e4ae425a6d2687f1a7e3ba17bc98c673636790f1b8ad91193c05875ef1
(3) c88b703fb08cbea894b6aeff5a544fb92e78a18e19814cd85da83b71f772aa6c
(4) 388c684f0ba1ef5017716adb5d21a053ea8e90277d0868337519f97bede61418
(5) 659cbb0e2411a44db63778987b1e22153c086a95eb6b18bdf89de078917abc63
(6) 82d052c865f5763aad42add438569276c00d3d88a2d062d36b2bae914d58b8c8
(7) aa3680d5d48a8283413f7a108367c7299ca73f553735860a87b08f39395618b7
(8) 0f62d96d6675f32685bbdb8ac13cda7c23436f63efbb9d07700d8669ff12b7c4
(9) 8d5366123cb560bb606379f90a0bfd4769eecc0557f1b362dcae9012b548b1e5

Mnemonic: candy maple cake sugar pudding cream honey rich smooth crumble sweet treat

⚠️  Important ⚠️  : This mnemonic was created for you by Truffle. It is not secure.
Ensure you do not use it on production blockchains, or else you risk losing funds.

truffle(development)>

This shows ten accounts (and their private keys) that can be used when interacting with the blockchain.

  1. On the Truffle Develop prompt, Truffle commands can be run by omitting the truffle prefix. For example, to run truffle compile on the prompt, type compile. The command to deploy your compiled contracts to the blockchain is truffle migrate. By default, truffle migrate will also run truffle compile, so you can just do the following:
migrate

You will see the following output:

Starting migrations...
======================
> Network name:    'develop'
> Network id:      4447
> Block gas limit: 6721975

1_initial_migration.js
======================

   Deploying 'Migrations'
   ----------------------
   > transaction hash:    0x3fd222279dad48583a3320decd0a2d12e82e728ba9a0f19bdaaff98c72a030a2
   > Blocks: 0            Seconds: 0
   > contract address:    0xa0AdaB6E829C818d50c75F17CFCc2e15bfd55a63
   > account:             0x627306090abab3a6e1400e9345bc60c78a8bef57
   > balance:             99.99445076
   > gas used:            277462
   > gas price:           20 gwei
   > value sent:          0 ETH
   > total cost:          0.00554924 ETH

   > Saving migration to chain.
   > Saving artifacts
   -------------------------------------
   > Total cost:          0.00554924 ETH

2_deploy_contracts.js
=====================

   Deploying 'ConvertLib'
   ----------------------
   > transaction hash:    0x97e8168f1c05fc40dd8ffc529b9a2bf45cc7c55b07b6b9a5a22173235ee247b6
   > Blocks: 0            Seconds: 0
   > contract address:    0xfb39FeaeF3ac3fd46e2123768e559BCe6bD638d6
   > account:             0x627306090abab3a6e1400e9345bc60c78a8bef57
   > balance:             99.9914458
   > gas used:            108240
   > gas price:           20 gwei
   > value sent:          0 ETH
   > total cost:          0.0021648 ETH

   Linking
   -------
   * Contract: MetaCoin <--> Library: ConvertLib (at address: 0xfb39FeaeF3ac3fd46e2123768e559BCe6bD638d6)

   Deploying 'MetaCoin'
   --------------------
   > transaction hash:    0xee4994097c10e7314cc83adf899d67f51f22e08b920e95b6d3f75c5eb498bde4
   > Blocks: 0            Seconds: 0
   > contract address:    0x6891Ac4E2EF3dA9bc88C96fEDbC9eA4d6D88F768
   > account:             0x627306090abab3a6e1400e9345bc60c78a8bef57
   > balance:             99.98449716
   > gas used:            347432
   > gas price:           20 gwei
   > value sent:          0 ETH
   > total cost:          0.00694864 ETH

   > Saving migration to chain.
   > Saving artifacts
   -------------------------------------
   > Total cost:          0.00911344 ETH

Summary
=======
> Total deployments:   3
> Final cost:          0.01466268 ETH

This shows the transaction IDs and addresses of your deployed contracts. It also includes a cost summary and real-time status updates.

Note: Your transaction hashes, contract addresses, and accounts will be different from the above.

Note: To see how to interact with the contract, please skip to the next section.

Migrate with Truffle Console

While Truffle Develop is an all-in-one personal blockchain and console, it spins up a very basic instance of ganache. You can also use a desktop application, to launch your personal blockchain, which is an easier to understand tool for those new to Ethereum and the blockchain, as it displays much more information up-front. Alternatively, if you want to customize your ganache instance using all the options available to you through the ganache CLI

The only extra step, aside from running Ganache, is that it requires editing the Truffle configuration file to point to the Ganache instance.

  1. Open truffle-config.js in a text editor. Replace the content with the following, ensuring your port number is correct:
module.exports = {
  networks: {
    development: {
      host: "127.0.0.1",
      port: 7545,
      network_id: "*"
    }
  }
};

This will allow a connection using Ganache's default connection parameters.

  1. Save and close that file.

  2. On the terminal, migrate the contract to the blockchain created by Ganache:

truffle migrate

You will see the following output:

```shell
Compiling your contracts...
===========================
> Everything is up to date, there is nothing to compile.


Starting migrations...
======================
> Network name:    'development'
> Network id:      1661545227029
> Block gas limit: 30000000 (0x1c9c380)


1_deploy_contracts.js
=====================

Deploying 'ConvertLib'
----------------------
> transaction hash:    0x259332521763056a5b949d33e3f52bff424c357b56af939ca46f96baa4386729
> Blocks: 0            Seconds: 0
> contract address:    0x7c31fB61DC4b817A7AFF135382FC85bcc9078f5e
> block number:        1
> block timestamp:     1661545283
> account:             0x0BD3Ea7C1CDE97e91e83615D7F6eF8910b3d0FEB
> balance:             999.999468208
> gas used:            157568 (0x26780)
> gas price:           3.375 gwei
> value sent:          0 ETH
> total cost:          0.000531792 ETH


Linking
-------
* Contract: MetaCoin <--> Library: ConvertLib (at address: 0x7c31fB61DC4b817A7AFF135382FC85bcc9078f5e)

Deploying 'MetaCoin'
--------------------
> transaction hash:    0x86b381fa96891e619a60a75db681d8aa95648b53572acc02690c9b94c76eadae
> Blocks: 0            Seconds: 0
> contract address:    0x03709DE4e1a3dA52505345Bd5129b48Ac891d63B
> block number:        2
> block timestamp:     1661545283
> account:             0x0BD3Ea7C1CDE97e91e83615D7F6eF8910b3d0FEB
> balance:             999.998107289579739204
> gas used:            416594 (0x65b52)
> gas price:           3.266773934 gwei
> value sent:          0 ETH
> total cost:          0.001360918420260796 ETH

> Saving artifacts
-------------------------------------
> Total cost:     0.001892710420260796 ETH

Summary
=======
> Total deployments:   2
> Final cost:          0.001892710420260796 ETH
```

This shows the transaction IDs and addresses of your deployed contracts. It also includes a cost summary and real-time status updates.

Note: Your transaction IDs and contract addresses may be different from the above.

  1. To interact with the contract, you can use the Truffle console. The Truffle console is similar to Truffle Develop, except it connects to an existing blockchain (in this case, the one generated by Ganache).
truffle console

You will see the following prompt:

truffle(development)>

Interact with the contract

Interact with the contract using the console in the following ways:

Note: We're using web3.eth.getAccounts() in these examples, which returns a promise which resolves to an array of all the accounts generated by the mnemonic. So, given the addresses generated by our mnemonic above, specifying (await web3.eth.getAccounts())[0] is equivalent to the address 0x627306090abab3a6e1400e9345bc60c78a8bef57.

As of Truffle v5, the console supports async/await functions, enabling much simpler interactions with the contract.

  • Begin by establishing both the deployed MetaCoin contract instance and the accounts created by either Truffle's built-in blockchain or Ganache:
truffle(development)> let instance = await MetaCoin.deployed()
truffle(development)> let accounts = await web3.eth.getAccounts()
  • Check the metacoin balance of the account that deployed the contract:
truffle(development)> let balance = await instance.getBalance(accounts[0])
truffle(development)> balance.toNumber()
  • See how much ether that balance is worth (and note that the contract defines a metacoin to be worth 2 ether):
truffle(development)> let ether = await instance.getBalanceInEth(accounts[0])
truffle(development)> ether.toNumber()
  • Transfer some metacoin from one account to another:
truffle(development)> instance.sendCoin(accounts[1], 500)
  • Check the balance of the account that received the metacoin:
truffle(development)> let received = await instance.getBalance(accounts[1])
truffle(development)> received.toNumber()
  • Check the balance of the account that sent the metacoin:
truffle(development)> let newBalance = await instance.getBalance(accounts[0])
truffle(development)> newBalance.toNumber()

Deploy to Mainnet, Testnet, and Beyond

If you want to deploy to alternative networks, consider using Truffle Dashboard. Just call truffle dashboard and deploy, test, and run the console using --network dashboard.

Continue learning

This quickstart showed you the basics of the Truffle project lifecycle, but there is much more to learn. Please continue on with the rest of our documentation and check out our unleashed series for the latest tutorials and interviews with industry experts!