Arb-L2-deposits

It is basically implementation of this idea suggested by 0xngmi: https://github.com/0xngmi/ideas#vault-for-arbing-withdrawals-on-l2-bridges Optimistic bridges have long withdrawal times so people that want their money instantly have to use bridges like synapse or hop to cross the gap instantly, and because of the way they work this creates some positive slippage if you bridge in.

This leads to an arbitrage opportunity, where you can bridge 1 ETH and get >1 ETH (eg: 1.01 ETH) on a L2. Afterwards you can withdraw that through the standard bridge, getting you >1 ETH back on ethereum.

Right now if you did this you could be getting 10-20% APY on ETH, which is much higher than on other yield aggregators and the risk profile is much lower (you only need to trust the bridge protocol the moment you are bridging, and apart from that only trust point is that L2 will work correctly, which is a very safe assumption).

The opportunity here is to build a protocol that automates this type of arbitrage, so people just deposit money on ethereum and the vault does everything for them. This opportunity is not open to traditional yield aggregators because they all work under the assumption that positions must be liquid.

Probably the hardest thing to build here is some algorithm that maximizes APY by leaving some money resting on L1 (you want to bridge when most people are exiting in order to maximize arbs).

The project uses foundry and has two contracts. One for the mainnet and one for the L2. The one on mainnet will use third party bridges to bridge from mainnet to L2. The one one L2 will use the official L2 bridge with a waiting period to bridge assets back. The interfaces for Arbitrum and Optimism are different in the case of the official bridge.