# start(with:) Validates a `BitcoinConfig` and starts the daemon with its arguments. ``` static func start(with config: BitcoinConfig) throws(ConfigError) where N : BitcoinNetwork ``` ## Parameters `config` The validated configuration to start the daemon with. ## Discussion Validation is performed before any daemon process is started. If a fatal `ConfigError` is thrown, the daemon is never started and `Daemon.waitUntilStopped()` must **not** be called. Non-fatal warnings are printed to stdout with an `⚠️` prefix. ```swift let auth = RPCAuth(username: "user", salt: "abc", passwordHMAC: "def") let config = BitcoinConfig.regtest().rpcAuth(auth).server() try Daemon.start(with: config) Daemon.waitUntilStopped() ``` > Throws: `ConfigError` if the configuration contains a fatal conflict.