Hyperlane Warp Routes Rebalancer

Hyperlane Warp Routes Rebalancer

Hyperlane is an interoperability protocol that lets blockchains talk to each other, enabling permissionless cross-chain messaging and asset transfers, without relying on a central authority.

Hyperlane Warp Routes (HWR) are cross-chain bridges that let you move tokens between different blockchains. Depending on the configuration, when you bridge a token through a warp route, tokens can be locked as collateral on the original chain and minted on the destination as synthetic tokens, or locked on the origin and released from the collateral pool on the destination.

Problem

Warp routes can include multiple chains as collateral sources, creating what's called Multi-Collateral warp routes. Take a USDC warp route that connects Optimism, Arbitrum, and a Custom Chain. Optimism and Arbitrum act as collateral chains, bridging USDC from either of these locks the tokens as collateral. The Custom Chain is set up as synthetic, so bridging USDC there mints new tokens instead of releasing existing ones.

Consider this scenario: I bridge 500 USDC from Arbitrum to the Custom Chain. The 500 USDC gets locked on Arbitrum, while 500 synthetic USDC is minted on the Custom Chain. Later, if I want to bridge 200 USDC from the Custom Chain to Optimism, the transaction would fail. Why? Because all 500 USDC is locked on Arbitrum, leaving zero liquidity available on Optimism to fulfill the withdrawal request. This liquidity imbalance prevents the bridge operation from completing, the classic cross-chain pain.

Note: This is a simplified example where all liquidity comes from a single transaction to illustrate the problem clearly.

Solution

The BootNode team implemented a rebalancer agent that monitors liquidity across all collateral chains and automatically moves tokens between them, as required. This prevents situations where a destination chain lacks sufficient collateral to fulfill withdrawal requests.

The rebalancer consists of 3 main modules:

Monitor

The monitor polls collateral balances at regular intervals defined in the rebalancer configuration. It also emits additional chain data, which is useful for metrics and logging.

Strategy

Based on collateral balances from the monitor, the strategy determines if rebalancing is needed and calculates the required token movements. For example, continuing from our earlier scenario, if the strategy requires all chains to maintain at least 200 USDC, it would determine that 300 USDC needs to move from Arbitrum to Optimism.

Rebalancer

The rebalancer executes the strategy by calling a newly added rebalance function on the collateral contracts. This initiates a bridge transaction using a specified bridge protocol (like USDC CCTP) to transfer the required amount between chains.

After rebalancing, Optimism would have the 200 USDC collateral needed to fulfill the withdrawal request.

Contribution

BootNode became a core contributor to the Hyperlane monorepo, where our team developed and shipped the rebalancer agent as a long-running service within the Hyperlane CLI. The implementation was merged into the main via PR #6044 on June 19, 2025 — now live and ready for teams scaling warp routes across chains.