# OCC Protocol With many iterations behind there are six smart contracts forming the core protocol layer: * **Mails**: Handles email-like messaging on the EVM * **Chat**: Provides a decentralized chat functionality on the EVM * **Users**: Manages user information (encryption public keys) * **AppFeeManager**: Manages fees and apps registration * **TierManager**: Manages tiers and fees discount * **Lock**: Locks ERC20 tokens for a specific period of time --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://wiki.4thtech.io/architecture/protocol.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.