> ## 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.

# Quick Start

## Overview

This is a quick start guide. If you have a vague idea about how CometBFT
works and want to get started right away, continue.

## Install

See the [install guide](/cometbft/v0.37/docs/guides/install).

## Initialization

Running:

```sh theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}}
cometbft init
```

will create the required files for a single, local node.

These files are found in `$HOME/.cometbft`:

```sh theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}}
$ ls $HOME/.cometbft

config  data

$ ls $HOME/.cometbft/config/

config.toml  genesis.json  node_key.json  priv_validator.json
```

For a single, local node, no further configuration is required.
Configuring a cluster is covered further below.

## Local Node

Start CometBFT with a simple in-process application:

```sh theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}}
cometbft node --proxy_app=kvstore
```

> Note: `kvstore` is a non persistent app, if you would like to run an application with persistence run `--proxy_app=persistent_kvstore`

and blocks will start to stream in:

```sh theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}}
I[01-06|01:45:15.592] Executed block                               module=state height=1 validTxs=0 invalidTxs=0
I[01-06|01:45:15.624] Committed state                              module=state height=1 txs=0 appHash=
```

Check the status with:

```sh theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}}
curl -s localhost:26657/status
```

### Sending Transactions

With the KVstore app running, we can send transactions:

```sh theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}}
curl -s 'localhost:26657/broadcast_tx_commit?tx="abcd"'
```

and check that it worked with:

```sh theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}}
curl -s 'localhost:26657/abci_query?data="abcd"'
```

We can send transactions with a key and value too:

```sh theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}}
curl -s 'localhost:26657/broadcast_tx_commit?tx="name=satoshi"'
```

and query the key:

```sh theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}}
curl -s 'localhost:26657/abci_query?data="name"'
```

where the value is returned in hex.

## Cluster of Nodes

First create four Ubuntu cloud machines. The following was tested on Digital
Ocean Ubuntu 16.04 x64 (3GB/1CPU, 20GB SSD). We'll refer to their respective IP
addresses below as IP1, IP2, IP3, IP4.

Then, `ssh` into each machine and install CometBFT following the [instructions](/cometbft/v0.37/docs/guides/install).

Next, use the `cometbft testnet` command to create four directories of config files (found in `./mytestnet`) and copy each directory to the relevant machine in the cloud, so that each machine has `$HOME/mytestnet/node[0-3]` directory.

Before you can start the network, you'll need peers identifiers (IPs are not enough and can change). We'll refer to them as ID1, ID2, ID3, ID4.

```sh theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}}
cometbft show_node_id --home ./mytestnet/node0
cometbft show_node_id --home ./mytestnet/node1
cometbft show_node_id --home ./mytestnet/node2
cometbft show_node_id --home ./mytestnet/node3
```

Finally, from each machine, run:

```sh theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}}
cometbft node --home ./mytestnet/node0 --proxy_app=kvstore --p2p.persistent_peers="ID1@IP1:26656,ID2@IP2:26656,ID3@IP3:26656,ID4@IP4:26656"
cometbft node --home ./mytestnet/node1 --proxy_app=kvstore --p2p.persistent_peers="ID1@IP1:26656,ID2@IP2:26656,ID3@IP3:26656,ID4@IP4:26656"
cometbft node --home ./mytestnet/node2 --proxy_app=kvstore --p2p.persistent_peers="ID1@IP1:26656,ID2@IP2:26656,ID3@IP3:26656,ID4@IP4:26656"
cometbft node --home ./mytestnet/node3 --proxy_app=kvstore --p2p.persistent_peers="ID1@IP1:26656,ID2@IP2:26656,ID3@IP3:26656,ID4@IP4:26656"
```

Note that after the third node is started, blocks will start to stream in
because >2/3 of validators (defined in the `genesis.json`) have come online.
Persistent peers can also be specified in the `config.toml`. See [here](/cometbft/v0.37/docs/core/configuration) for more information about configuration options.

Transactions can then be sent as covered in the single, local node example above.