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Arquitectura

Bridge Contracts Architecture

Hardhat v2 + Foundry project implementing LayerZero V2 OFT (Omnichain Fungible Token) for cross-chain bridging.

{% hint style="info" %} This project lives on the master branch (not main). {% endhint %}

Tech Stack

• Hardhat v2 for compilation and deployment scripts
• Foundry for testing (not installed locally -- CI only)
• LayerZero V2 OFT standard
• Solidity 0.8.x

OFT Concept

LayerZero's OFT standard enables tokens to be natively bridged across chains without wrapped representations. The token contract itself handles lock/burn on the source chain and mint/unlock on the destination chain.

The adapter contracts handle the LayerZero messaging. Each chain has a token contract and an adapter. When a user bridges from Base to Polygon:

1. Tokens are locked/burned on Base via the adapter
2. LayerZero relays the message to Polygon
3. Tokens are minted/unlocked on Polygon via the adapter

Supported Chains

Chain	LayerZero Endpoint ID	Usage
Base	30184	Primary chain
Polygon	30109	Secondary chain

Bridge Routes

Bridge routes are configured in the backend database (bridge_route table), not in the contracts. Each route maps:

• bridge_token_key -- Logical token identifier (e.g., ARGT)
• ops_token_id -- Reference to the token on a specific network
• network -- Chain where this route endpoint exists
• adapter_address -- OFT adapter contract address on that chain
• lz_eid -- LayerZero endpoint ID for that chain

A token like ARGT has two routes (one per chain) grouped by the same bridge_token_key.

Local Development

Foundry is not installed locally. Use Hardhat for compilation:

Code
cd twin-bridge
npx hardhat compile

For Foundry-based tests, use CI or install Foundry separately:

Code
curl -L https://foundry.paradigm.xyz | bash
foundryup
forge test

Deployment

Deployment scripts are in scripts/. Each chain requires a separate deployment with the correct LayerZero endpoint configuration. After deploying, the adapter addresses must be registered in the backend bridge_route table for the dashboard and platform to use them.