L1 → L2 Message Testing with Anvil-ZKsync

This guide shows you how to locally test a cross-chain message from L1 → L2 using anvil and anvil-zksync.

Prerequisites

1. Start Local Nodes

Start the L1 and L2 nodes in two terminals:

# L1 (Anvil)
anvil --no-request-size-limit --port 8012

# L2 (Anvil-ZkSync)
anvil-zksync --evm-interpreter --external-l1=http://127.0.0.1:8012

The --evm-interpreter flag enables deploying EVM contracts to L2, simplifying Hardhat workflows.

You now have:

  • L1 RPC at http://127.0.0.1:8012
  • L2 RPC at http://127.0.0.1:8011

2. Clone the Example Repo

git clone git@github.com:dutterbutter/cross-chain-example.git
cd cross-chain-example
npm install

Repo layout:

├── contracts             # AccessKey (L1) & Vault (L2)
├── test/l1-l2.spec.ts    # Full e2e test using Hardhat + ethers

3. What the Contracts Do

AccessKey.sol (L1)

Sends a cross-chain message to unlock a vault on L2 via the Bridgehub.

Vault.sol (L2)

Accepts an unlock() call and marks itself as unlocked. Validates the caller using aliased L1 address logic.

Environment Variables

Ensure .env contains:

PRIVATE_KEY=0x...      # Use pre-funded dev accounts from anvil-zksync

4. Run the Test

This test:

  • Deploys AccessKey to L1
  • Deploys Vault to L2 with the aliased address of the L1 AccessKey
  • Calls AccessKey.unlockVaultOnL2(...) to dispatch a message via Bridgehub
  • Waits for L2 state change to confirm message success

Compile contracts first:

npm run compile

Run the test:

npm run test

Want EraVM Contracts Instead?

If you’re interested in deploying EraVM contracts instead of EVM contracts using @matterlabs/hardhat-zksync, check out the eravm-test branch of the repository. Everything else stays the same — nodes, config, and test flow.

✅ Success Criteria

At the end of the test, you should see:

✓ should deploy AccessKey on L1, Vault on L2, then unlock (XXXXms)

And Vault.isVaultUnlocked() on L2 should return true.