Node.js script to merge dust UTXOs.

• This script finds all unspent UTXOs, sorts them by address.
• It selects an address with two or more dust inputs (configurable threshold).
• It builds a transaction with up to 677 UTXOs from the selected address.
• The script sends the transaction and displays the transaction ID.
• Can run once or continuously with configurable intervals.
• WARNING: This is done without user intervention!

Requirements

• Node.js LTS (20.x or later, use nvm if possible)
• Blackcoin More v26.2.0 or later RPC server

Setup

1. Copy example.config.js to config.js

cp example.config.js config.js

2. Update config.js with your settings:

   • host: RPC server host (default: localhost)
   • port: RPC server port (default: 15715)
   • user: RPC username
   • pass: RPC password
   • rpcwallet: Your wallet name (check ~/.blackmore/wallets/ for mainnet or ~/.blackmore/testnet/wallets/ for testnet)
   • dustThreshold: Maximum satoshi value to consider as dust (default: 6000)
   • intervalMinutes: How often to check for dust UTXOs
     • Set to 0 to run once and exit
     • Set to 60 to run every hour
     • Set to 1440 to run once daily

3. Ensure your wallet is loaded and unlocked before running the script

4. Make sure your blackmore.conf has at least:

server=1
daemon=1
rpcuser=yourusername
rpcpassword=yourpassword

How to run

Install dependencies:

npm install

Run once:

npm run start
# or
node index.js

Continuous Mode

Set intervalMinutes in config.js to enable continuous monitoring:

intervalMinutes: 60  // Check every hour

When running in continuous mode:

• The script will run immediately on startup
• It displays a countdown timer showing when the next check will run
• The timer updates every 10 seconds
• Press Ctrl+C to stop the script

Example Output

Continuous mode enabled. Will check for dust UTXOs every 60 minutes.
Press Ctrl+C to stop.

Searching for Addresses with UTXOs with amount less than or equal to 6000
Found 345 total UTXOs
Address BKDvboD1CzZ5KycP1FRSXRoi7XXhHoQhS1 has 42 dust UTXOs
Found 1 addresses with multiple dust UTXOs
Selecting from 42 dust UTXOs for address: BKDvboD1CzZ5KycP1FRSXRoi7XXhHoQhS1
Selected 42 UTXOs, total input amount: 939000000 sat (9.39 BLK)
[12/6/2025, 2:30:45 PM] Next check in 0h 59m 50s
[12/6/2025, 2:30:55 PM] Next check in 0h 59m 40s

Troubleshooting

• "Wallet is locked" error: Unlock your wallet with:

blackmore-cli -rpcwallet=YourWalletName walletpassphrase "your-passphrase" 300

• No dust found: Adjust the dustThreshold in config.js to a higher value

• Script stops: Check that your RPC credentials are correct and the wallet is loaded

How the Script Works

1. Fetches UTXOs: Retrieves all unspent transaction outputs from your wallet via RPC
2. Groups by address: Organizes UTXOs by their addresses
3. Identifies dust: Finds addresses with multiple UTXOs below the dust threshold
4. Selects UTXOs: Picks up to 677 dust UTXOs from the address with the most dust
5. Calculates fees: Creates a transaction to estimate size and calculates transaction fees (100 sat/byte + 100 sat minimum)
6. Adjusts amount: Recreates the transaction with the calculated fee deducted from the output
7. Signs & sends: Signs the transaction with your wallet's private key and broadcasts it
8. Displays TXID: Shows the transaction ID upon successful broadcast

Important Notes

• Wallet must be loaded: Ensure your wallet specified in rpcwallet is loaded in the Blackcoin daemon
• Wallet must be unlocked: For signing transactions, your wallet must be unlocked (see Troubleshooting)
• Automatic execution: The script sends transactions without user confirmation
• RPC connection: Requires an RPC connection to the Blackcoin More daemon on the configured host and port
• Maximum UTXOs per transaction: Limited to 677 UTXOs per transaction (blockchain limitation)

Configuration Limits

• dustThreshold: Can be any positive integer in satoshis
  • Recommended range: 600 to 100,000,000 satoshis
  • Each satoshi = 0.00000001 BLK
• intervalMinutes: Can be any positive integer or 0
  • Practical minimum: 5 minutes (for testing)
  • Recommended for production: 60+ minutes

Deployment

You can run this script as a background service or schedule it with cron:

# Run every hour via cron
0 * * * * cd /path/to/merge-dust && npm run start

Or use a process manager like PM2:

pm2 start index.js --name merge-dust