# Building Modules This repository contains documentation on concepts developers need to know in order to build modules for Cosmos SDK applications. 1. [Introduction to Cosmos SDK Modules](./intro.md) 2. [`AppModule` Interface and Module Manager](./module-manager.md) 3. [Messages and Queries](./messages-and-queries.md) 4. [`Msg` services - Processing Messages](./msg-services.md) 5. [Query Services - Processing Queries](./query-services.md) 6. [BeginBlocker and EndBlocker](./beginblock-endblock.md) 7. [`Keeper`s](./keeper.md) 8. [Invariants](./invariants.md) 9. [Genesis](./genesis.md) 10. [Module Interfaces](./module-interfaces.md) 11. [Standard Module Structure](./structure.md) 12. [Errors](./errors.md) 13. [In-Place Store Migrations](./upgrade.md)