zkSync Messenger L1->L2 Example

Send a message from L1 Goerli to L2 zkSync testnet.

Example

There's two contracts; L1Contract.sol and L2Contract.sol

The L1 contract has a method sendGreetingMessageToL2 that sends a message to L2 contract to set a greeting message on L2 contract. It sends the encoded calldata to execute setGreeting on L2 which can only be called if the message was sent by the L1 contract.

Files

• L2Contract.sol
• L1Contract.sol
• deployL1.js
• deployL2.js
• sendL1ToL2Message.js
• waitForInclusion.js
• getGreetingOnL2.js

Install

git clone https://github.com/miguelmota/zksync-messenger-l1-to-l2-example.git
cd zksync-messenger-l1-to-l2-example
npm install

Set Signer

Create .env

PRIVATE_KEY=123...

Make sure private key has funds on both zkSync testnet and Goerli.

Compile Contracts

npx hardhat compile

Deploy L1 Contract

Command

npx hardhat run --network goerli scripts/deployL1.js

Output

deployed to 0xbb027F3d45CEb4c9F8F1FaB6c7Bad5053A66c9b0

Deploy L2 Contract

Command

L1_CONTRACT=0xbb027F3d45CEb4c9F8F1FaB6c7Bad5053A66c9b0 \
npx hardhat deploy-zksync --network zksync

Output

deployed to 0xdA90933EAC728c6e9AF0f5403514439a4Bb6ae90

Send L1->L2 Message

Command (replace env vars with your values)

GREETING="hello world" \
L1_CONTRACT=0xbb027F3d45CEb4c9F8F1FaB6c7Bad5053A66c9b0 \
L2_CONTRACT=0xdA90933EAC728c6e9AF0f5403514439a4Bb6ae90 \
npx hardhat run --network goerli scripts/sendL1ToL2Message.js

Output

sent tx hash 0x70b1c11f608a2319fd07dc64f6a0de35ce4e1d483fe0c2a8f09be45c61fb035b
https://goerli.etherscan.io/tx/0x70b1c11f608a2319fd07dc64f6a0de35ce4e1d483fe0c2a8f09be45c61fb0

Wait for L1 Block Inclusion

Command

L1_TX_HASH=0x70b1c11f608a2319fd07dc64f6a0de35ce4e1d483fe0c2a8f09be45c61fb035b \
npx hardhat run --network zksync scripts/waitForInclusion.js

Output

Waiting for L2 block inclusion (this may take up to 20 minutes)...
{
  to: '0xdA90933EAC728c6e9AF0f5403514439a4Bb6ae90',
  from: '0xbb027F3d45CEb4c9F8F1FaB6c7Bad5053A66c9b0',
  contractAddress: null,
  transactionIndex: 0,
  ...
  l1BatchNumber: 626758,
  l1BatchTxIndex: 123,
  l2ToL1Logs: [ ... ],
  byzantium: true
}

Get Greeting on L2

Command

L2_CONTRACT=0xdA90933EAC728c6e9AF0f5403514439a4Bb6ae90 \
npx hardhat run --network zksync scripts/getGreetingOnL2.js

Output

greeting: hello world

License

MIT @ Miguel Mota