README.md

Starknet Messaging Testbed

Sending messages from Ethereum to Starknet.

Starknet Contract Deployment:

cd starknet/

1. Set up your Starknet account

Set the required Starknet environment variables in starknet.env and run:

source starknet.env

2. Build the Cairo contract

(cd store_value && scarb build)

3. Declare the Cairo contract in Starknet

In other words, you're sending your contract’s code to the network

starkli declare \
	store_value/target/dev/store_value_SimpleStorage.contract_class.json \
	--compiler-version=2.7.1 \

This will return the identifier of the contract class in Starknet:

Class hash declared:
0x0618a9355cb653ac5cc7eb0d4d88ad74fbbb30bff03357dc573641010aed4279

4. Deploy a contract instance to Starknet

You're now creating a usable instance of the code you previously declared

starkli deploy 0x0618a9355cb653ac5cc7eb0d4d88ad74fbbb30bff03357dc573641010aed4279

This will return the address of the deployed contract:

Contract deployed:
0x05d6d1ab1a3ce77fbf0e04eca3a17e908ef9825e86286dc3845c5e23bb82485c

Ethereum Contract Deployment:

Install dependencies

cd ethereum/
pnpm i

Set the required Ethereum environment variables in ethereum.env and run:

source ethereum.env

1. Build the Solidity contract

Compile the Ethereum smart contract using hardhat

npx hardhat compile

2. Deploy the contract to Ethereum

npx hardhat run scripts/deploy.js --network sepolia

This will return the Ethereum address of the deployed contract:

L1 to L2 Messenger deployed to: 0x76d4661bD8a04e5769bA196d91f5D33f5038cdBc

3. Call the Contract

Review the callContract.js script and update all variables accordingly. Once you're done, run it with:

node scripts/callContract.js

Checking everything worked

You should now be able to call your L2 contract with starkli and check that modified_by has been updated to reflect your L1 contract address, and the stored value corresponds with what you sent:

starkli call <L2_CONTRACT_ADDRESS> get_modified_by

[
    "<LI_CONTRACT_ADDRESS>"
]
starkli call <L2_CONTRACT_ADDRESS> get

[
    "<NEW_VALUE>"
]