A witness node represents a full node in the network that verifies all transactions and blocks against its local state. Hence, we recommend all service providers to run an maintain their own witness nodes for reliability and security reasons.

It takes a –data-dir parameter to define a working and data directory to store the configuration, blockchain and local databases. Those will be automatically created with default settings if they don’t exist locally set.

Launching a witness node

The witness is launched according to:

./programs/witness_node/witness_node --data-dir="mydata"


The configuration file config.ini in mydata is commented and contains the following essential settings:

# Endpoint for P2P node to listen on
# p2p-endpoint =

# P2P nodes to connect to on startup (may specify multiple times)
# seed-node =

# Pairs of [BLOCK_NUM,BLOCK_ID] that should be enforced as checkpoints.
# checkpoint =

# Endpoint for websocket RPC to listen on
# rpc-endpoint =

# Endpoint for TLS websocket RPC to listen on
# rpc-tls-endpoint =

# The TLS certificate file for this server
# server-pem =

# Password for this certificate
# server-pem-password =

# File to read Genesis State from
# genesis-json = sep-18-testnet-genesis.json

# JSON file specifying API permissions
# api-access = apiaccess.json

# Enable block production, even if the chain is stale.
enable-stale-production = false

# Percent of witnesses (0-99) that must be participating in order to produce blocks
required-participation = false

# Allow block production, even if the last block was produced by the same witness.
allow-consecutive = false

# ID of witness controlled by this node (e.g. "1.6.5", quotes are required, may specify multiple times)
# witness-id =

# Tuple of [PublicKey, WIF private key] (may specify multiple times)
# private-key = ["pubkey","wif-key"]

# Account ID to track history for (may specify multiple times)
# track-account =

# Track market history by grouping orders into buckets of equal size measured in seconds specified as a JSON array of numbers
# bucket-size = [15,60,300,3600,86400]

# How far back in time to track history for each bucket size, measured in the number of buckets (default: 1000)
# history-per-size = 1000

Enabling Remote Procedure Calls (RPC)

In order to allow RPC calls for blockchain operations you need to modify the following entry in the configuration file:

rpc-endpoint =

This will open the port 8090 for global queries only. Since the witness node only maintains the blockchain and (unless you are an actively block producing witness) no private keys are involved, it is safe to expose your witness to the internet.

Restarting the witness node

When restarting the witness node, it may be required to append the –replay-blockchain parameter to regenerate the local (in-memory) blockchain state.