> ## 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.

# SDK Go Packages

> The Cosmos SDK is a collection of Go modules. This section provides documentation on various packages that can be used when developing a Cosmos SDK chain. It lists all standalone Go modules that are part of the Cosmos SDK.

The Cosmos SDK is a collection of Go modules. This section provides documentation on various packages that can be used when developing a Cosmos SDK chain.

<Tip>
  For more information on SDK modules, see the [SDK Modules](/sdk/latest/modules/modules) section.
  For more information on SDK tooling, see the [Tooling](/sdk/latest/guides/tooling/tool-guide) section.
</Tip>

## Core

* [Core](https://pkg.go.dev/cosmossdk.io/core) - Core library defining SDK interfaces ([ADR-063](/sdk/latest/reference/architecture/adr-063-core-module-api))
* [API](https://pkg.go.dev/cosmossdk.io/api) - API library containing generated SDK Pulsar API
* [Store](https://pkg.go.dev/cosmossdk.io/store) - Implementation of the Cosmos SDK store

## State Management

* [Collections](https://pkg.go.dev/cosmossdk.io/collections) - Typed state management library with automatic key encoding, iteration, and secondary indexes. See the [Collections guide](/sdk/latest/guides/state/collections).
* [ORM](https://pkg.go.dev/cosmossdk.io/orm) - ORM-style state layer built on top of collections, providing table abstractions with primary and secondary indexes. Based on [ADR-055](/sdk/latest/reference/architecture/adr-055-orm).

## Automation

* [Client/v2](https://pkg.go.dev/cosmossdk.io/client/v2) - Library powering [AutoCLI](/sdk/latest/guides/tooling/autocli)

## Transactions

* [x/tx](https://pkg.go.dev/cosmossdk.io/x/tx) - Transaction signing types, sign mode implementations (direct, amino JSON, textual), and transaction decoder utilities.

## Utilities

* [Log](https://pkg.go.dev/cosmossdk.io/log) - Logging library
* [Errors](https://pkg.go.dev/cosmossdk.io/errors) - Error handling library
* [Math](https://pkg.go.dev/cosmossdk.io/math) - Math library for SDK arithmetic operations

## SimApp

* [SimApp](https://pkg.go.dev/cosmossdk.io/simapp) - SimApp is a sample Cosmos SDK chain used for testing and development.