> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cosmos.network/llms.txt
> Use this file to discover all available pages before exploring further.

# Guides Overview

> Deep dives into specific Cosmos SDK topics for developers who have completed the tutorial.

These guides go deeper on specific topics. If you've completed the [Build a Chain Tutorial](/sdk/latest/tutorials/example/00-overview) and want to learn more about a particular area, this is where to look.

## Module Design

Best practices and architectural patterns for building well-structured modules.

* [Module Design Considerations](/sdk/latest/guides/module-design/module-design-considerations): module boundaries, state layout, privileged operations, and inter-module dependencies
* [Object-Capability Model](/sdk/latest/guides/module-design/ocap): how the SDK uses keeper interfaces to scope access between modules

## ABCI

How your application interacts with CometBFT at the protocol level, including advanced features such as mempool design and vote extensions.

* [ABCI Overview](/sdk/latest/guides/abci/abci): CheckTx, PrepareProposal, ProcessProposal, FinalizeBlock
* [Application Mempool](/sdk/latest/guides/abci/app-mempool): custom mempool implementations and transaction ordering
* [Vote Extensions](/sdk/latest/guides/abci/vote-extensions): injecting application data into the consensus process

## Tooling

Tools available to Cosmos SDK developers.

* [Tool Guide](/sdk/latest/guides/tooling/tool-guide): overview of all available tools by category
* [Writing CLI Commands](/sdk/latest/guides/tooling/autocli): AutoCLI and hand-written commands
* [Confix](/sdk/latest/guides/tooling/confix): managing and migrating node configuration

## State

How modules store and access state.

* [Module Store Internals](/sdk/latest/guides/state/store): KVStore, prefix stores, and the multistore
* [Collections API](/sdk/latest/guides/state/collections): the modern Collections framework for module state

## Upgrades and Migrations

How to upgrade modules and chains without downtime.

* [Upgrading Modules](/sdk/latest/guides/upgrades/upgrade): consensus versions, migration handlers, and store upgrades
* [Cosmovisor](/sdk/latest/guides/upgrades/cosmovisor): automated binary upgrade management

## Testing and Observability

Testing your modules and monitoring a running chain.

* [Module Simulation](/sdk/latest/guides/testing/simulator): fuzz testing with the SDK's simulation framework
* [Telemetry](/sdk/latest/guides/testing/telemetry): metrics and instrumentation
* [Log v2](/sdk/latest/guides/testing/log): structured logging with zerolog and OpenTelemetry