Configuration#

A node reads a HOCON configuration file whose settings live under the dcc key. Built-in defaults (application.conf and network-defaults.conf) are merged with your file, so your file only needs the settings you want to change.

Note

Verified against node-scala v1.7.0. Do not use the shipped application.conf as your own config file; it is a defaults file.

Environment variables (Docker)#

The Docker entrypoint translates these variables into JVM options:

Variable	Default	Effect
`DCC_NETWORK`	`mainnet`	Sets `dcc.defaults.blockchain.type` — the network the node joins
`DCC_HEAP_SIZE`	`2g`	JVM `-Xmx`
`DCC_LOG_LEVEL`	`INFO`	Console log level: `OFF`, `ERROR`, `WARN`, `INFO`, `DEBUG`, `TRACE`
`DCC_REST_API_BIND`	`127.0.0.1`	Sets `dcc.rest-api.bind-address`
`DCC_WALLET_SEED`	—	Base58 wallet seed, written to a private temporary config file at start-up and then unset
`DCC_WALLET_PASSWORD`	—	Wallet file password, handled the same way
`JAVA_OPTS`	—	Extra JVM options

To use your own file, mount it at /etc/dcc/dcc.conf. The entrypoint loads it automatically and layers wallet secrets on top. DCC_WALLET_SEED and DCC_WALLET_PASSWORD only take effect when such a file is mounted (and no command arguments are passed to the container); without /etc/dcc/dcc.conf they are ignored.

Ports and network defaults#

Network	P2P port	Minimum connections
Mainnet	6868	5
Testnet	6863	5

The REST API listens on port 6869 on every network. Known peers for each network ship in network-defaults.conf.

Note

The public DecentralChain Testnet (testnet-node.decentralchain.io) is a custom chain (dcc.blockchain.type = CUSTOM, chain ID !) whose nodes use P2P port 6868. The built-in testnet profile (DCC_NETWORK=testnet) uses port 6863 and its own known peers, so a node started with it will not join the public Testnet; use a custom config matching the Testnet’s genesis and peers instead.

Commonly changed settings#

Key	Default	Description
`dcc.directory`	`""`	Base directory for node data
`dcc.db.max-rollback-depth`	`2000`	Maximum number of blocks a rollback can undo
`dcc.db.store-transactions-by-address`	`true`	Index transactions by address (needed by address history endpoints)
`dcc.wallet.file`	`<directory>/wallet/wallet.dat`	Wallet file path
`dcc.wallet.password`	unset	Wallet file password
`dcc.wallet.seed`	unset	Base58 seed; if unset the node generates one
`dcc.rest-api.enable`	`yes`	Turn the REST API on or off
`dcc.rest-api.bind-address`	`127.0.0.1`	Interface the API listens on
`dcc.rest-api.port`	`6869`	API port
`dcc.rest-api.api-key-hash`	`""`	Hash of the API key that protects privileged endpoints
`dcc.rest-api.cors-headers.access-control-allow-origin`	`""`	Set to a specific origin in production
`dcc.rest-api.transactions-by-address-limit`	`1000`	Max results for address transaction history
`dcc.rest-api.blocks-request-limit`	`100`	Max blocks per range request
`dcc.utx.max-size`	`100000`	Max unconfirmed transactions held
`dcc.network.max-inbound-connections`	`100`	Inbound peer limit
`dcc.network.max-outbound-connections`	`100`	Outbound peer limit
`dcc.hotstuff.enabled`	`false`	Experimental fast-finality engine — leave off (see Features and Activation)

API key#

Privileged endpoints (wallet, rollback, /debug/*, /node/stop) require an X-Api-Key header. The node stores only a hash of the key. Generate the hash with the node itself:

curl -X POST http://localhost:6869/utils/hash/secure \
  -H 'Content-Type: text/plain' -d 'my-secret-api-key'

Put the hash value from the JSON response in dcc.rest-api.api-key-hash, restart, and send my-secret-api-key in X-Api-Key.

Example: minimal Mainnet file#

dcc {
  directory = "/var/lib/dcc"
  rest-api {
    bind-address = "127.0.0.1"
    api-key-hash = "<hash from /utils/hash/secure>"
  }
  wallet {
    password = "change-me"
  }
}