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DevChain Quick Start

The Simple Way
var account = new Account("0xb5b1870957d373ef0eeffecc6e4812c0fd08f554b37b233526acc331bf1544f7");
var devChain = new DevChainNode();
await devChain.StartAsync(account);
var web3 = devChain.CreateWeb3(account);

That's it. A full Ethereum node running in your process — no Docker, no binaries, no setup.

Nethereum DevChain is a complete in-process Ethereum node. It runs the full EVM (up to Prague hardfork), mines blocks instantly, and gives you funded accounts out of the box. This guide gets you from zero to a working local chain in under a minute.

Prerequisites​

dotnet add package Nethereum.DevChain

You also need Nethereum.Web3 for the Account class and Web3 interactions (it's a transitive dependency of Nethereum.DevChain).

Create and Start a Node​

The basic workflow is: create a node, start it with funded accounts, then create a Web3 instance connected to it.

using Nethereum.DevChain;
using Nethereum.Web3;
using Nethereum.Web3.Accounts;

// Create an account from a private key
var account = new Account("0xb5b1870957d373ef0eeffecc6e4812c0fd08f554b37b233526acc331bf1544f7");

// Create and start the dev chain — account gets 10,000 ETH
var devChain = new DevChainNode();
await devChain.StartAsync(account);

// Create a Web3 instance wired directly to the in-process node (no HTTP)
var web3 = devChain.CreateWeb3(account);

The CreateWeb3 extension method creates a Web3 instance that talks to the node via an in-process RPC dispatcher — no network overhead, no port conflicts.

Send Your First Transaction​

With web3 connected, use all the standard Nethereum APIs as if you were talking to mainnet:

// Check balance
var balance = await web3.Eth.GetBalance.SendRequestAsync(account.Address);
Console.WriteLine($"Balance: {Web3.Convert.FromWei(balance.Value)} ETH");

// Transfer ETH
var receipt = await web3.Eth.GetEtherTransferService()
    .TransferEtherAndWaitForReceiptAsync("0xde0b295669a9fd93d5f28d9ec85e40f4cb697bae", 1.0m);

Console.WriteLine($"TX Hash: {receipt.TransactionHash}");
Console.WriteLine($"Block:   {receipt.BlockNumber}");

Since AutoMine is enabled by default, transactions are mined instantly — TransferEtherAndWaitForReceiptAsync returns immediately.

Configuration​

DevChainConfig controls chain behavior. The defaults work for most cases, but you can customise:

var config = new DevChainConfig
{
    ChainId = 1337,             // Default: 1337
    BlockGasLimit = 30_000_000, // Default: 30M
    AutoMine = true,            // Default: true (mine on each tx)
    InitialBalance = BigInteger.Parse("10000000000000000000000")  // Default: 10,000 ETH
};

var devChain = new DevChainNode(config);
await devChain.StartAsync(account);

For Hardhat or Anvil compatibility (ChainId 31337, same mnemonic), use the presets:

var devChain = new DevChainNode(DevChainConfig.Hardhat);
var devChain = new DevChainNode(DevChainConfig.Anvil);

Multiple Accounts​

Generate and fund multiple accounts automatically:

var devChain = new DevChainNode();
await devChain.StartAsync();

// Generate 5 accounts, each funded with the default 10,000 ETH
var accounts = await devChain.GenerateAndFundAccountsAsync(5);

var aliceWeb3 = devChain.CreateWeb3(accounts[0]);
var bobWeb3 = devChain.CreateWeb3(accounts[1]);

Or pass specific accounts at startup:

var alice = new Account("0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80");
var bob = new Account("0x59c6995e998f97a5a0044966f0945389dc9e86dae88c7a8412f4603b6b78690d");

await devChain.StartAsync(alice, bob);

Factory Methods​

For quick one-liners, use the static factory methods:

// Create, configure, and start in one call
var devChain = await DevChainNode.CreateAndStartAsync(account);
var web3 = devChain.CreateWeb3(account);

Storage Options​

By default, DevChain uses SQLite for blocks/transactions/receipts/logs and in-memory storage for account state. The SQLite database is deleted automatically when the node is disposed.

Fully in-memory (fastest, no disk I/O):

var devChain = DevChainNode.CreateInMemory();
await devChain.StartAsync(account);

Persistent storage (data survives restarts):

var devChain = new DevChainNode(DevChainConfig.Default, "./mychain/chain.db", persistDb: true);
await devChain.StartAsync(account);

Cleanup​

DevChainNode implements IDisposable. Call Dispose() when you're done — it cleans up SQLite files and releases resources:

devChain.Dispose();

Or use using for automatic cleanup:

using var devChain = new DevChainNode();
await devChain.StartAsync(account);
// ... use the chain ...
// Automatically disposed at end of scope

Aspire dashboard showing DevChain, Explorer, Indexer, Bundler, and PostgreSQL

Next Steps​