> For the complete documentation index, see [llms.txt](https://zchains.gitbook.io/zchains-whitepaper/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://zchains.gitbook.io/zchains-whitepaper/architecture/modules/minimal.md).

# Minimal

### Overview

As mentioned before, ZChains is a set of different modules, all connected to each other.\
\
The **Blockchain** is connected to the **State**, or for example, **Synchronization**, which pipes new blocks into the **Blockchain**.

**Minimal** is the cornerstone for these inter-connected modules. It acts as a central hub for all the services that run on the ZChains.

### Startup Magic

Among other things, Minimal is responsible for:

* Setting up data directories
* Creating a keystore for libp2p communication
* Creating storage
* Setting up consensus
* Setting up the blockchain object with GRPC, JSON RPC, and Synchronization

```go
func NewServer(logger hclog.Logger, config *Config) (*Server, error) {
	m := &Server{
		logger: logger,
		config: config,
		chain:      config.Chain,
		grpcServer: grpc.NewServer(),
	}

	m.logger.Info("Data dir", "path", config.DataDir)

	// Generate all the paths in the dataDir
	if err := setupDataDir(config.DataDir, dirPaths); err != nil {
		return nil, fmt.Errorf("failed to create data directories: %v", err)
	}

	// Get the private key for the node
	keystore := keystore.NewLocalKeystore(filepath.Join(config.DataDir, "keystore"))
	key, err := keystore.Get()
	if err != nil {
		return nil, fmt.Errorf("failed to read private key: %v", err)
	}
	m.key = key

	storage, err := leveldb.NewLevelDBStorage(filepath.Join(config.DataDir, "blockchain"), logger)
	if err != nil {
		return nil, err
	}
	m.storage = storage

	// Setup consensus
	if err := m.setupConsensus(); err != nil {
		return nil, err
	}

	stateStorage, err := itrie.NewLevelDBStorage(filepath.Join(m.config.DataDir, "trie"), logger)
	if err != nil {
		return nil, err
	}

	st := itrie.NewState(stateStorage)
	m.state = st

	executor := state.NewExecutor(config.Chain.Params, st)
	executor.SetRuntime(precompiled.NewPrecompiled())
	executor.SetRuntime(evm.NewEVM())

	// Blockchain object
	m.blockchain, err = blockchain.NewBlockchain(logger, storage, config.Chain, m.consensus, executor)
	if err != nil {
		return nil, err
	}

	executor.GetHash = m.blockchain.GetHashHelper

	// Setup sealer
	sealerConfig := &sealer.Config{
		Coinbase: crypto.PubKeyToAddress(&m.key.PublicKey),
	}
	m.Sealer = sealer.NewSealer(sealerConfig, logger, m.blockchain, m.consensus, executor)
	m.Sealer.SetEnabled(m.config.Seal)

	// Setup the libp2p server
	if err := m.setupLibP2P(); err != nil {
		return nil, err
	}

	// Setup the GRPC server
	if err := m.setupGRPC(); err != nil {
		return nil, err
	}

	// Setup jsonrpc
	if err := m.setupJSONRPC(); err != nil {
		return nil, err
	}

	// Setup the syncer protocol
	m.syncer = protocol.NewSyncer(logger, m.blockchain)
	m.syncer.Register(m.libp2pServer.GetGRPCServer())
	m.syncer.Start()

	// Register the libp2p GRPC endpoints
	proto.RegisterHandshakeServer(m.libp2pServer.GetGRPCServer(), &handshakeService{s: m})

	m.libp2pServer.Serve()
	return m, nil
}
```