The bitcoin node can be started in the testnet mode if you want to test the Bitcoin network and run an experiment. This is a faster network as compared to the live network and has relaxed rules for mining and transactions.
Various faucet services are available for the bitcoin test network. One example is Bitcoin TestNet sandbox, where users can request bitcoins to be paid to their testnet bitcoin address.
This can be accessed via https://testnet.manu.backend.hamburg/.
This is very useful for experimentation with transactions on testnet.
The command line to start up testnet is as follows:
bitcoind --testnet -daemon bitcoin-cli --testnet <command> bitcoin-qt --testnet
