> ## Documentation Index
> Fetch the complete documentation index at: https://starkware-9575960b-starkzapv3.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Deploying the HelloStarknet contract locally

<Warning>
  If you encounter an issue while following this tutorial, see [Troubleshooting](/build/quickstart/appendix#troubleshooting).
</Warning>

## Introduction

Welcome to the third installment of the *Deploy your first contract* guide! 🥇

Local networks, also known as development networks or *devnets*, enable a fast and private development process, making them ideal for taking your first Starknet steps. This installment of the series will therefore guide you through the steps necessary to declare, deploy, and interact with the `HelloStarknet` contract on your very own local instance of Starknet.

## Initializing a local Starknet instance

A local Starknet instance can be easily initialized using Starknet Devnet by simply running:

```bash theme={null}
starknet-devnet --seed=0
```

<Note>
  The `--seed` option is used to force consistent addresses of predeployed account (see more details below).
</Note>

If successful, the result should resemble the following:

```console theme={null}
Chain ID: SN_SEPOLIA (0x534e5f5345504f4c4941)

Predeployed FeeToken
ETH Address: 0x49D36570D4E46F48E99674BD3FCC84644DDD6B96F7C741B1562B82F9E004DC7
Class Hash: 0x9524A94B41C4440A16FD96D7C1EF6AD6F44C1C013E96662734502CD4EE9B1F
STRK Address: 0x4718F5A0FC34CC1AF16A1CDEE98FFB20C31F5CD61D6AB07201858F4287C938D
Class Hash: 0x76791EF97C042F81FBF352AD95F39A22554EE8D7927B2CE3C681F3418B5206A

Predeployed UDC
Address: 0x41A78E741E5AF2FEC34B695679BC6891742439F7AFB8484ECD7766661AD02BF
Class Hash: 0x7B3E05F48F0C69E4A65CE5E076A66271A527AFF2C34CE1083EC6E1526997A69

...
```

<Note>
  Starknet Devnet should keep running for the following sections to work.
</Note>

## Fetching a predeployed account

<Tip>
  To learn more about Starknet accounts, check out the [Accounts section](/learn/protocol/accounts/).
</Tip>

To interact with your local Starknet instance, you first need an account. Luckily, the result of initializing a local Starknet instance using Starknet Devnet should also include a list of predeployed accounts that resembles the following:

```console theme={null}
| Account address |  0x064b48806902a367c8598f4f95c305e8c1a1acba5f082d294a43793113115691
| Private key     |  0x0000000000000000000000000000000071d7bb07b9a64f6f78ac4c816aff4da9
| Public key      |  0x039d9e6ce352ad4530a0ef5d5a18fd3303c3606a7fa6ac5b620020ad681cc33b

| Account address |  0x078662e7352d062084b0010068b99288486c2d8b914f6e2a55ce945f8792c8b1
| Private key     |  0x000000000000000000000000000000000e1406455b7d66b1690803be066cbe5e
| Public key      |  0x007a1bb2744a7dd29bffd44341dbd78008adb4bc11733601e7eddff322ada9cb

...
```

This allows to avoid creating and deploying new accounts, and instead simply importing them to Starknet Foundry. To import your local node's first predeployed account, use a new terminal window to navigate into the `hello_starknet` directory created in [Generating `HelloStarknet`](/build/quickstart/hellostarknet#creating-hellostarknet) and run:

```bash theme={null}
sncast account import \
    --address=0x064b48806902a367c8598f4f95c305e8c1a1acba5f082d294a43793113115691 \
    --type=oz \
    --url=http://127.0.0.1:5050 \
    --private-key=0x0000000000000000000000000000000071d7bb07b9a64f6f78ac4c816aff4da9 \
    --add-profile=devnet \
    --silent
```

<Tip>
  To learn more about `sncast account import`, see the [Starknet Foundry documentation](https://foundry-rs.github.io/starknet-foundry/appendix/sncast/account/import.html).
</Tip>

If successful, the result should resemble the following:

```console theme={null}
Success: Account imported successfully

Account Name: account-1
Add Profile:  Profile devnet successfully added to /app/snfoundry.toml
```

## Declaring `HelloStarknet` locally

Before a contract can be deployed on Starknet, its compiled code needs to be submitted to the network (also known as *declaring* it).

<Tip>
  To learn more about distinction between deploying a contract and declaring it, see [the Cairo Book](https://book.cairo-lang.org/ch100-01-contracts-classes-and-instances.html).
</Tip>

To declare the `HelloStarknet` contract, run:

```bash theme={null}
sncast --profile=devnet declare \
    --contract-name=HelloStarknet
```

If successful, the result should resemble the following:

```console theme={null}
Success: Declaration completed

Class Hash:       0x51e0d3b26fb79035afdc64d2214eb18291629b4f2ef132e79c3f3fbe1ba57c4
Transaction Hash: 0x76e28641d96ee0788f5a960931ee717c5dae36f95f227c02d5578a6898d8af3
```

where `class_hash` is the contract's class hash, which can then be used to deploy an instance of it.

<Tip>
  To learn more about the class hashes, check out [the Cairo Book](https://book.cairo-lang.org/ch100-01-contracts-classes-and-instances.html).
</Tip>

## Deploying `HelloStarknet` locally

With `HelloStarknet` declared, you can now deploy an instance of it by running:

```bash theme={null}
sncast --profile=devnet deploy \
    --class-hash=0x051e0d3b26fb79035afdc64d2214eb18291629b4f2ef132e79c3f3fbe1ba57c4 \
    --salt=0
```

<Note>
  The `--salt` option is used to force a consistent address for the deployed contract.
</Note>

If successful, the result should resemble the following:

```console theme={null}
Success: Deployment completed

Contract Address: 0x04035c4db7822523478996bfc2b80d925e671279bb99ed1fb4e4fcc222e344e6
Transaction Hash: 0x04d11358b809c7b8a5aae1a1cf0e72e0b436fb2d0a2dd1a26d009fec7aa74280
```

## Interacting with `HelloStarknet` locally

Now that your instance of `HelloStarknet` is deployed, you can interact with via its functions by either calling or invoking them.

Calling is used for read functions that don't modify their contract's storage, and allows querying a smart contract function without sending a transaction. For example, you can call `HelloStarknet`'s `get_balance` function by running:

```bash theme={null}
sncast --profile=devnet call \
    --contract-address=0x04035c4db7822523478996bfc2b80d925e671279bb99ed1fb4e4fcc222e344e6 \
    --function=get_balance
```

If successful, the result should resemble the following:

```console theme={null}
Success: Call completed

Response:     0x0
Response Raw: [0x0]
```

Invoking is used for write functions that modify their contract's storage, and submits a transaction to the network that changes its state. For example, you can invoke `HelloStarknet`'s `increase_balance` function by running:

```bash theme={null}
sncast --profile=devnet invoke \
    --contract-address=0x04035c4db7822523478996bfc2b80d925e671279bb99ed1fb4e4fcc222e344e6 \
    --function=increase_balance \
    --arguments=42
```

If successful, the result should resemble the following:

```console theme={null}
Success: Invoke completed

Transaction Hash: 0x02691af0fb2b720b27ae17c844d72244b8fc35f3a3d57b6549736d9a88f8f014
```

You can verify that your deployed contract's storage — and by extension, the state of your local Starknet instance — has indeed changed by calling `get_balance` again. If all goes well, the result should resemble the following ($42_{10} = 2a_{16}$):

```console theme={null}
Success: Call completed

Response:     0x2a
Response Raw: [0x2a]
```