Yerba

Yerba is an experimental library that abstracts away the complexity of fragmented token balances across multiple OP Stack chains. Designed for developers building multichain applications, Yerba provides a set of tools to aggregate token balances, enabling payments on a specific chain without requiring user interaction with bridges.

The core concept is simple: users shouldn’t have to think about where their funds are. Yerba handles the process of fetching and aggregating liquidity from other chains in the background, enabling smooth and frictionless payments on the target chain. While Yerba is built as a generalized library, we showcase its capabilities with a use case: a digital café menu where users can pay for coffee in USDC on Base (Chain A), even if their balances are distributed across other chains like Worldchain (Chain B) or Optimism (Chain C).

The system is composed of a Multicaller Contract on the home chain that coordinates balance queries and token aggregation, a Forwarder Contract authorized by the user to manage cross-chain operations, a Smart Account should be deployed on destination chains to handle token transfers using bridges --not there for simplicity this time. The project uses Supersim to simulate and test the multichain environment, ensuring smooth interactions across chains.