# Base Token Adjuster
This crate contains all the logic to handle ZK Chain with custom base tokens.
## Overview
### The Base Token Ratio Persister
Contains the building blockss for the `BaseTokenRatioPersisterLayer`.
- Connects with external APIs to get the current price of the base token and of ETH.
- Persists the ETH<->BaseToken ratio in the database.
- Upon certain configured threshold, update the L1 ETH<->BaseToken conversion ratio.
### The Base Token Ratio Provider
Contains the building blocks for the `BaseTokenRatioProviderLayer`.
- Periodically fetches from the DB and caches the latest ETH<->BaseToken conversion ratio.
- Exposes this ratio upon request.