---
title: Accounts for testing
sidebar_position: 3
description: Ethereum accounts used for Besu testing only on private networks
---

> For AI agents: a documentation index is available at [/llms.txt](/llms.txt). Append `.md` to any documentation URL to get the markdown source.


import TestAccounts from '../../global/test_accounts.md';

# Accounts for testing

You can use existing accounts for testing by including them in the genesis file for a private network. Besu also provides predefined accounts for use in development mode.

## Development mode

When you start Besu with the [`--network=dev`](../../public-networks/reference/cli/options.md#network) command line option, Besu uses the `dev.json` genesis file by default.

The `dev.json` genesis file defines the following accounts used for testing.

<TestAccounts />

## Genesis file

To use existing test accounts, specify the accounts and balances in a genesis file for your test network. For an example of how to define accounts in the genesis file, see [`dev.json`](https://github.com/hyperledger/besu/blob/750580dcca349d22d024cc14a8171b2fa74b505a/config/src/main/resources/dev.json).

To start Besu with the genesis file defining the existing accounts, use the [`--genesis-file`](../../public-networks/reference/cli/options.md#genesis-file) command line option .