Deployment Guide

This guide covers deploying the Flash Loan Router contracts to blockchain networks using Forge deployment scripts.

Overview

The Flash Loan Router consists of three main contracts:

FlashLoanRouter: Main entry point for flash loan settlements
AaveBorrower: Adapter for Aave flash loans
ERC3156Borrower: Adapter for ERC-3156 compliant lenders (e.g., Maker)

All contracts are deployed deterministically using CREATE2 with the same addresses across all supported networks.

Environment Setup

Create environment file

Copy the .env.example file to .env in the project root:

cp .env.example .env

Configure environment variables

Edit .env and set the required variables:

# Network configuration
CHAIN_ID=1  # Target network chain ID
ETH_RPC_URL=https://eth-mainnet.g.alchemy.com/v2/YOUR_API_KEY
PRIVATE_KEY=0x...  # Deployer private key

# Optional: For contract verification
ETHERSCAN_API_KEY=your_etherscan_api_key

# Optional: For single contract deployments
# FLASHLOAN_ROUTER_ADDRESS=0x9da8B48441583a2b93e2eF8213aAD0EC0b392C69

Load environment variables

Source the environment file before running deployment commands:

source .env

Deploy All Contracts

For new network deployments, use the DeployAllContracts script to deploy all three contracts in a single transaction.

Dry-run the deployment

Test the deployment without broadcasting transactions:

forge script script/DeployAllContracts.s.sol:DeployAllContracts \
  --rpc-url $ETH_RPC_URL \
  --private-key $PRIVATE_KEY

Review the output to ensure expected contract addresses and gas costs.

Broadcast deployment

Execute the actual deployment:

forge script script/DeployAllContracts.s.sol:DeployAllContracts \
  --rpc-url $ETH_RPC_URL \
  --private-key $PRIVATE_KEY \
  --broadcast

Deploy with verification

For Etherscan verification, add the --verify flag:

forge script script/DeployAllContracts.s.sol:DeployAllContracts \
  --rpc-url $ETH_RPC_URL \
  --private-key $PRIVATE_KEY \
  --broadcast \
  --verify

Ensure ETHERSCAN_API_KEY is set in your .env file for verification to succeed.

Deploy Single Contract

To deploy individual contracts on existing networks, use the single-deployment scripts.

FlashLoanRouter

forge script script/single-deployment/DeployFlashLoanRouter.s.sol:DeployFlashLoanRouter \
  --rpc-url $ETH_RPC_URL \
  --private-key $PRIVATE_KEY \
  --broadcast

AaveBorrower

forge script script/single-deployment/DeployAAVEBorrower.s.sol:DeployAAVEBorrower \
  --rpc-url $ETH_RPC_URL \
  --private-key $PRIVATE_KEY \
  --broadcast

ERC3156Borrower

forge script script/single-deployment/DeployERC3156Borrower.s.sol:DeployERC3156Borrower \
  --rpc-url $ETH_RPC_URL \
  --private-key $PRIVATE_KEY \
  --broadcast

Update Deployment Records

After successful deployment, update the networks.json file to track contract addresses.

Generate networks.json

Run the generation script to update deployment records:

bash script/generate-networks-file.sh > networks.json

This script reads broadcast files from broadcast/ directory and generates the updated networks.json.

Manual updates (if needed)

For networks deployed outside of Forge scripts, manually update broadcast/networks-manual.json before regenerating.

Verify addresses

Check that networks.json contains the correct addresses for your deployed contracts:

{
  "FlashLoanRouter": {
    "1": {
      "address": "0x9da8b48441583a2b93e2ef8213aad0ec0b392c69",
      "transactionHash": "0x..."
    }
  },
  "AaveBorrower": { ... },
  "ERC3156Borrower": { ... }
}

Deployment Architecture

The deployment process uses CREATE2 for deterministic addresses:

FlashLoanRouter is deployed first with the CoW Settlement contract address
Borrower contracts are deployed with the FlashLoanRouter address as constructor argument
All deployments use a fixed salt (Constants.SALT) for address determinism
If a contract already exists at the computed address, deployment is skipped

Troubleshooting

CREATE2 collision error

This occurs when a contract already exists at the computed CREATE2 address. The deployment scripts automatically detect existing contracts and skip re-deployment.For single deployments requiring the FlashLoanRouter address, set the FLASHLOAN_ROUTER_ADDRESS environment variable.

Verification fails

Common causes:

Missing or invalid ETHERSCAN_API_KEY
Network not supported by Etherscan API
Constructor arguments mismatch

See the Contract Verification guide for manual verification steps.

Insufficient funds

Ensure the deployer account has sufficient native tokens (ETH, MATIC, etc.) for:

Contract deployment gas costs
Multiple contract deployments if using DeployAllContracts

Next Steps

Contract Verification

Verify deployed contracts on block explorers

Supported Networks

View all deployed contract addresses by network

Contracts

Hooks Trampoline

Composable CoW

Contracts SDK

Flash Loan Router

Overview

Environment Setup

Deploy All Contracts

Deploy Single Contract

FlashLoanRouter

AaveBorrower

ERC3156Borrower

Update Deployment Records

Deployment Architecture

Troubleshooting

Next Steps

Contract Verification

Supported Networks

​Overview

​Environment Setup

​Deploy All Contracts

​Deploy Single Contract

​FlashLoanRouter

​AaveBorrower

​ERC3156Borrower

​Update Deployment Records

​Deployment Architecture

​Troubleshooting

​Next Steps

Contract Verification

Supported Networks

Overview

Environment Setup

Deploy All Contracts

Deploy Single Contract

FlashLoanRouter

AaveBorrower

ERC3156Borrower

Update Deployment Records

Deployment Architecture

Troubleshooting

Next Steps