Token Bridging

Syndicate appchains use the Arbitrum Standard Bridge for token bridging. This is the canonical lock-and-mint mechanism used by Arbitrum, ensuring compatibility and security for your appchain's assets.

How the Arbitrum Standard Bridge Works

The Arbitrum Standard Bridge allows you to move ERC-20 tokens between your settlement chain (the parent chain, e.g., Ethereum) and your appchain (the child chain) with no custom bridge contracts required. Here's how it works at a high level:

1. Deploy or use an existing ERC-20 token on your settlement chain.
2. Approve the bridge gateway contract to spend your tokens on your settlement chain.
3. Initiate a deposit using the bridge UI or SDK. The bridge locks (escrows) your tokens on your settlement chain and sends a message to the appchain.
4. A corresponding token contract is automatically created on the appchain (if it doesn't already exist), and the equivalent amount of tokens is minted to your address.
5. Withdrawals work in reverse: tokens are burned on the appchain, and the equivalent amount is released to your address on the settlement chain after a challenge period.

Key components:

• Router contract: Handles routing of bridge requests to the correct gateway.
• Gateway contract: Escrows or burns tokens on the source chain and mints or releases them on the destination chain.
• Automatic token deployment: The first time a token is bridged, a standard token contract is automatically deployed on the appchain.

For a step-by-step guide and more technical details, see the Arbitrum Standard Bridge documentation.