> ## 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.

# Tool Guide

> What tools should I use and for what? A practical guide to the Cosmos SDK developer toolbox.

A practical reference for Cosmos chain and module developers: what each tool does and when to reach for it.

## Code generation

**[Buf](https://buf.build/cosmos/cosmos-sdk/docs/main)** — Compiles `.proto` files into Go types, gRPC stubs, and REST gateway code. The standard way to run `proto-gen` in a Cosmos project. Also lints and formats proto files, and publishes generated docs to the Buf registry. See the [Protobuf Documentation](https://buf.build/cosmos/cosmos-sdk/docs/main) on the Buf registry.

**[Protobuf Annotations](/sdk/latest/guides/reference/protobuf-annotations)** — Cosmos SDK-specific proto field options (scalar descriptors, amino names, query pagination, etc.) that affect code generation output. Consult this when writing `.proto` files for a new module.

**[AutoCLI](/sdk/latest/guides/tooling/autocli)** — Generates CLI commands and gRPC-gateway routes for your module's messages and queries directly from proto definitions. Use it instead of hand-writing CLI commands — it also handles pagination, output formatting, and custom flag mappings.

## Client library

**[CosmJS](https://github.com/cosmos/cosmjs)** — The official JavaScript and TypeScript library for building clients, frontends, and scripts that interact with Cosmos chains. Handles transaction signing, broadcasting, querying, and wallet integration in browser and Node.js environments.

## State management

**[Collections](/sdk/latest/guides/state/collections)** — A typed abstraction over raw `KVStore` access. Handles key encoding, prefix isolation, iteration, and secondary indexes. Also produces a schema used automatically by simulation decoders. Use it for all new module state instead of raw byte keys.

**[Store](/sdk/latest/guides/state/store)** — Reference documentation for the SDK store layer: `KVStore`, `CommitMultiStore`, `CacheKVStore`, IAVL, pruning strategies, and store versioning. Read this when you need to understand what is happening under the collections abstraction or need to work with stores directly.

## Testing

**[Testing](/sdk/latest/learn/concepts/testing)** — The SDK's testing conventions: unit tests for keepers and message servers, integration tests wired with `depinject`, and end-to-end tests using the `testnet` package.

**[Module Simulation](/sdk/latest/guides/testing/simulator)** — A fuzz-testing framework that runs your module's messages with randomized inputs and genesis states. Checks for panics, non-determinism, and import/export inconsistencies. Use it to catch edge cases that unit tests miss.

## Node setup and operations

**[Prerequisites](/sdk/latest/node/prerequisites)** — Required software and environment setup before running a node.

**[Run a Node](/sdk/latest/node/run-node)** — How to initialize a chain, configure genesis, and start a node with `simd`.

**[Run a Testnet](/sdk/latest/node/run-testnet)** — Running a local multi-node testnet using `simd testnet`.

**[Production Deployment](/sdk/latest/node/run-production)** — Hardening and deployment guidance for running a node in production: systemd, state sync, backup strategies, and security considerations.

**[Cosmovisor](/sdk/latest/guides/upgrades/cosmovisor)** — A process manager for your chain binary that watches for on-chain upgrade proposals and automatically swaps in the new binary at the correct upgrade height. Required for zero-downtime upgrades in production.

**[Confix](/sdk/latest/guides/tooling/confix)** — A CLI tool for reading, setting, migrating, and diffing `app.toml` and `client.toml` configuration files across SDK versions. Use it when upgrading a node between SDK versions or scripting config changes.

## Keys and transactions

**[Keyring](/sdk/latest/node/keyring)** — The SDK's key management layer. Covers keyring backends (`os`, `file`, `test`, `memory`), key types, and how to manage keys via `simd keys`. Use this to understand key storage security trade-offs in production deployments.

**[Building Transactions](/sdk/latest/node/txs)** — How to programmatically construct, sign, encode, and broadcast transactions using the SDK's `TxBuilder` and `TxConfig` APIs.

**[Interacting with a Node](/sdk/latest/node/interact-node)** — Using the CLI and gRPC to query state and broadcast transactions against a running node.

## Observability

**[Telemetry](/sdk/latest/guides/testing/telemetry)** — OpenTelemetry-based metrics for the SDK and your modules. Emit counters, gauges, and histograms from keeper methods. Integrates with Prometheus and any OTLP-compatible backend.

**[Logging](/sdk/latest/guides/testing/log)** — Structured logging via `cosmossdk.io/log` (backed by zerolog). Use it in keepers and servers to emit structured log lines, with support for log correlation and OpenTelemetry log export.

## IBC

**[IBC Go](/ibc)** — The canonical IBC implementation for Cosmos SDK chains. Use it to add cross-chain token transfers and arbitrary message passing to your chain.