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Node Configuration

The Nano node software is designed to run with little or no configuration. All configuration options have defaults that can be changed using TOML configuration files, by passing configuration values via the command line, or a combination of the two methods.

Automatic migration and backups of JSON files

Versions prior to 20 use JSON as the configuration file format, and these will be automatically migrated to TOML files on startup. Note that only non-default values are migrated.

In version 19.0 when the node is upgraded between releases, including any beta releases, all config files will be backed up prior to the upgrade in the same directory for easy recovery if needed.

As TOML files are never upgraded by the node, no backups are created for these.

V19.0 and earlier config.json file

Below is a complete example of the config.json file used by V19.0 and earlier:

    "version": "(int)", // Wallet version
    "wallet": "(string)", // Default wallet to load on boot (only for GUI wallet)
    "account": "(string)", // Default account to load on boot (only for GUI wallet)
    "node": {
        "version": "(int)", // Node version
        "peering_port": "7075", // Default node port
        "bootstrap_fraction_numerator": "1",
        "enable_voting": "false", // Enable or disable voting for blocks. If disabled, saves some resources
        "receive_minimum": "1000000000000000000000000", // Minimum import receivable, default 1 Rai
        "logging": {
            "ledger": "false", // Track incoming blocks
            "ledger_duplicate": "false",
            "network": "true", // Track general network info like forks
            "network_timeout": "false", // Track TCP socket disconnections due to timeout
            "network_message": "false",
            "network_publish": "false", // Track blocks you publish to
            "network_packet": "false", // Track packets origin
            "network_keepalive": "false", // Track keepalive messages
            "network_node_id_handshake": "false", // Track node_id messages
            "node_lifetime_tracing": "false",
            "insufficient_work": "true",
            "bulk_pull": "false", // Bootstrap related logging
            "work_generation_time": "true",
            "log_to_cerr": "false",
            "max_size": "16777216", // Max size of logs before old files deletion. Default is 16MB
            "rotation_size": "4194304", // Size of Log File before rotation in bytes, Default is 4MB
            "version": "(int)", // Logging config version
            "vote": "false", // Track voting activities
            "flush": "true",  // Setting this to false gives better performance, but may lose entries on crashes.
            "upnp_details": "false", // Determines if upnp discovery details are logged (default off to avoid sharing device info when shipping logs)
            "timing": "false", // Logs durations of key functions, such as batch verification, etc.
            "log_ipc": "true", // Logging of IPC related messages
            "min_time_between_output": "5", // Minimum time between log calls, in ms
            "single_line_record": "false" // Log each record in single line (including block content & election results with votes)
        "vote_minimum": "1000000000000000000000000000000000",// Prevents voting if delegated weight is under this threshold
        "work_peers": "", // Delegate a node your hash work, you need to get RPC access to that node
        "preconfigured_peers": [ // List of defaults peers to connect on boot
        "preconfigured_representatives": [ // List of defaults representatives, which you delegate voting weight, of your wallet
        "online_weight_minimum": "60000000000000000000000000000000000000", // Online weight minimum required to confirm block
        "online_weight_quorum": "50", // Percentage of votes required to rollback blocks
        "password_fanout": "1024",
        "io_threads": "4",
        "work_threads": "4", // PoW work threads. By default all available CPU threads, set lower value for 24/7 services
        "callback_address": "::ffff:", // Callback IP address, in sample IPv4 localhost
        "callback_port": "17076", // Callback port
        "callback_target": "/", // Callback target, in sample root of callback listening server
        "bootstrap_connections": "16", // Multi-connection bootstrap. Should be a power of 2.
        "bootstrap_connections_max": "4", // Allowed incoming bootstrap connections count. Lower value save IOPS & bandwidth. 64 recommended for high-end fast nodes, 0 for HDD home users,
        "lmdb_max_dbs": "128", // Maximum open DBs (MAX_DBS, increase default if more than 100 wallets required
        "block_processor_batch_max_time": "5000", // Number of milliseconds the block processor works at a time
        "allow_local_peers": "false", // To allow local host peering
        "signature_checker_threads": "1", // Number of threads to use for verifying signatures
        "unchecked_cutoff_time": "14400", // Number of seconds unchecked entry survives before being cleaned
        "tcp_io_timeout": "15", // Timeout in seconds for TCP connect-, read- and write operations
        "pow_sleep_interval": "0", // The amount to sleep after each batch of POW calculations. Reduces max CPU usage at the expensive of a longer workgeneration time.
        "external_address": "::",
        "external_port": "0",
        "tcp_incoming_connections_max": "1024", // Allowed incoming TCP connections count
        "websocket": {
            "enable": "false",
            "address": "::1", // Default IPv6 address to listen on. If using Docker, change address to ::ffff: to listen on all interfaces within the container.
            "port": "7078"
        "ipc": { // For more details about these options see the IPC section below
            "tcp": {
                "enable": "false",
                "port": "7077",
                "io_timeout": "15"
            "local": {
                "version": "1",
                "enable": "false",
                "allow_unsafe": "false",
                "path": "\/tmp\/nano",
                "io_timeout": "15"
        "diagnostics": {
                "txn_tracking": {
                    "enable": "false", // Tracks lmdb transactions
                    "min_read_txn_time": "5000", // Logs stacktrace when read transactions are held longer than this time (milliseconds)
                    "min_write_txn_time": "500", // Logs stacktrace when write transactions are held longer than this time (milliseconds)
                    "ignore_writes_below_block_processor_max_time": "true" // Ignore any block processor writes less than block_processor_max_time
        "use_memory_pools": "true", // Improve performance by using memory pools (Note: Memory allocated will be reused but never reclaimed, if having memory issues then try turning this off)
        "confirmation_history_size": "2048", // Controls confirmation history size, default setting preserves existing behavior
        "bandwidth_limit": "5242880", // Outbound voting traffic limit in bytes/sec after which messages will be dropped
        "vote_generator_delay": "100", // Delay in ms before votes are sent out to allow for better bundling of hashes in votes
        "vote_generator_threshold": "3", // Defines the point at which the node will delay sending votes for another vote_generator_delay. Allows for more hashes to be bundled under load
        "active_elections_size": "50000", // Limits number of active elections in container before dropping will be considered (other conditions must also be satisfied), minimum value allowed is 250.
        "conf_height_processor_batch_min_time": "50", // Amount of time in ms to batch setting confirmation heights for accounts during high tps to reduce write I/O bottlenecks.
        "backup_before_upgrade": "false", // Backup ledger & wallet databases before each upgrade
        "work_watcher_period": "5", // Time between checks for confirmation and re-generating higher difficulty work if unconfirmed, for blocks in the work watcher
        "max_work_generate_multiplier": "256.0", // Maximum allowed difficulty multiplier for work generation (double). Used for work_generate RPC requests & internal wallet work watcher
        "frontiers_confirmation": "auto" // Mode for force frontiers confirmation. "auto" mode (default): If not Principal Representative, start frontier confirmation process every 15 minutes; if Principal Representative, start frontier confirmation process every 3 minutes. "always": Start frontier confirmation process every 3 minutes. "disabled": Do not start frontier confirmation process
    "rpc_enable": "true", // Enable (in-process or child process) or disable RPC. Out of process rpc servers can still be used if launched manually.
    "rpc": {
        "enable_sign_hash": "true",
        "version": "1",
        "child_process": {
            "enable": "false", // Whether the rpc server is run as a child process rather than in-process
            "rpc_path": "C:\\Users\\Wesley\\Documents\\raiblocks\\build\\Debug\\nano_rpc.exe", // The nano_rpc executable to run if enabled (Windows example).
    "opencl_enable": "false", // Enable GPU hashing
    "opencl": {
        "platform": "0", // Platform ID
        "device": "0", // Device ID
        "threads": "1048576"

Configuration file locations

The node and its related processes will look for the files listed below, either in their default location or the location specified with --data_path. These files are optional. The table includes a command which can be used to generate a documented TOML file with defaults suitable for the system.

Name Description Generated with
config-node.toml Node configuration nano_node --generate_config node
config-rpc.toml RPC configuration nano_node --generate_config rpc
config-nano-pow-server.toml Proof of work server configuration nano_pow_server --generate_config
config-qtwallet.toml Qt developer wallet configuration This file is maintained by the Qt wallet

The default locations of the config files are listed in the table below.

OS Location
Windows C:\Users\<user>\AppData\Local\NanoTest\
macOS /Users/<user>/Library/NanoTest/
Linux /home/<user>/NanoTest/
Docker As defined by the -v flag in the docker run command
.deb/rpm /var/nanocurrency/NanoTest
OS/Build Location
Windows C:\Users\<user>\AppData\Local\Nano\
macOS /Users/<user>/Library/Nano/
Linux /home/<user>/Nano/
Docker As defined by the -v flag in the docker run command
.deb/rpm /var/nanocurrency/Nano
OS Location
Windows C:\Users\<user>\AppData\Local\NanoBeta\
macOS /Users/<user>/Library/NanoBeta/
Linux /home/<user>/NanoBeta/
Docker As defined by the -v flag in the docker run command
.deb/rpm /var/nanocurrency/NanoBeta

Options formatting

Config options are referred to in the documentation using the format category.option where category can be multiple levels. For example, the node.enable_voting option would correspond to the following entry in the TOML file:


# Enable or disable voting. Enabling this option requires additional system resources, namely increased CPU, bandwidth and disk usage.
# type:bool
enable_voting = true

While a multiple category option like node.websocket.enable would correspond to this TOML file entry:


# Enable or disable WebSocket server.
# type:bool
enable = false

Passing config values on the command line

Instead of changing the config file, config values can be passed in via the --config option, which can be repeated multiple times.

Example that enables the RPC and WebSocket servers:

nano_node --config rpc.enable=true --config node.websocket.enable=true

The way strings are passed is as follows:
v22+ uses quotes (") such as:

nano_node --config"api/callback"
Arrays must not have spaces inbetween entries.

v21 and earlier must use escaped quotes (\") such as:

nano_node --config\"api/callback\"
For backwards compatibility this is also supported in v22+

Mixing config options on the command line and TOML files

If a config file exists, config values passed in via the command line will take precedence.

Notable configuration options

As of V20.0 the sample TOML packaged with the binaries and available for generation via the command line are commented out with descriptions of each option. Where applicable the following integration areas have those options included along with additional context where necessary.

Work generation

See the Work Generation guide.


See the WebSockets Integration guide.



To enable communication via RPC, set this configuration option in the config-node.toml file.


# Enable or disable RPC
# type:bool
enable = true


This configuration option is set in the config-rpc.toml file.

Due to their sensitive or dangerous nature, certain RPC calls/options require this setting to be enabled before they can be used. Examples of RPC calls that require this include:

  • stop: allows you to completely stop the node from running
  • work_generate: allows potential consumption of CPU or GPU resources on the node or attached work peers to generate PoW
  • send: can be used to transfer available funds in the wallet to another account
  • Various other wallet and resource-heavy operations
# Enable or disable control-level requests.
# WARNING: Enabling this gives anyone with RPC access the ability to stop the node and access wallet funds.
# type:bool
enable_control = false

Dangerous RPC calls controlled by enable_control

Due to the sensitive or dangerous nature of these calls, caution should be used when considering setting enable_control to true in your config file. It is highly recommended to only enable this when RPC ports are listening exclusively to local or loopback IP addresses or other measure are put in place outside the node to limit RPC access to dangerous calls. For more details see the Node Security page.

More advanced options for controlling the process the RPC server runs under can be found in the Running Nano as a service guide.


Known Issue Windows V21: Crash when using config node.logging.stable_log_filename

Setting node.logging.stable_log_filename configuration option to true results in a node crash on Windows in V21.0 and V21.1, after a node restart. This must be set to false.

This configuration option is set in the config-node.toml file.

By default this option is set to false which results in all log files having a timestamp appended to them, even the currently active file. If set to true the currently active log file will have a static name at log/node.log for easier management.


# Append to log/node.log without a timestamp in the filename.
# The file is not emptied on startup if it exists, but appended to.
# type:bool
stable_log_filename = true


This configuration option is set in the config-rpc.toml file.

By default, all RPC calls and the time spent handling each one are logged. This can be optionally turned off by switching option logging.log_rpc to false


# Whether to log RPC calls.
# type:bool
log_rpc = true


See the IPC Integration guide.


See the Voting as a Representative guide.

Ledger backends

See the Ledger Management guide.

HTTPS support

See the HTTPS Support guide.

HTTP callback


When possible, using a WebSocket is recommended as it provides more efficiency, more options for types of information to receive and better control over the volume of notifications with filtering.

These configuration options are set in the config-node.toml file.


# Callback address.
# type:string,ip
#address = ""

# Callback port number.
# type:uint16
#port = 0

# Callback target path.
# type:string,uri
#target = ""

JSON POST requests with every confirmed block are sent to the callback server as defined in the config values above: http://callback_address:callback_port<callback_target>. Callback target should include a leading slash.

For details on how to integrate using the HTTP callback, see the HTTP Callback section of the Integration Guides.

Network Details

Port Type Default Details
7075 TCP Enabled
  • Node bootstrapping server
  • Share port configuration in config-node.toml, option node.peering_port
  • Binds to all adapters; unicast
  • Contents: Raw nano protocol stream
  • Transmits the ledger to new nodes in bulk
  • If blocked other nodes will not be able retrieve the ledger from this node
7076 TCP Disabled
  • RPC server
  • Port configurable in config-rpc.toml, option rpc.port
  • Enable in config-node.toml, option rpc.enable or by starting nano_rpc manually
  • Binds to localhost by default for security reasons, configurable in config-rpc.toml, option rpc.address; unicast
  • Contents: Unencrypted HTTP requests containing JSON object bodies
  • Allows the node to be queried or controlled through HTTP requests
  • If blocked the node will not be able to be queried or controlled by HTTP
  • WARNING: Exposing this port externally while setting enable_control option to true in configs could expose your wallet, allow the node to be stopped remotely and open your node up to other dangerous activity. See the Node Security page for more details.
7078 TCP Disabled
  • Websocket server
  • Port configurable in config-node.toml, option node.websocket.port
  • Enable in config-node.toml, option node.websocket.enable
  • Binds to localhost by default due to data throughput potentially being very high; producer-subscriber broadcast
  • Contents: Standard websocket frames containing JSON-encoded objects
  • See WebSocket Support for details on configuration

UDP disabled by default, deprecated

As of V21 peering and communicating via UDP has been disabled by default and is deprecated. The ability to use UDP will be removed from the node in a future release yet to be determined.