In general, the term “node” simply refers to a device that plays a part in a larger network. In the context of crypto, nodes are computers and servers that run the blockchain software and store information about the network. So blockchain can be described as a set of nodes that holds an identical version of the blockchain data and validates transactions conducted within the network.
Anyone can set up a node by downloading the blockchain’s software onto their personal computer or server anywhere in the world. In addition, nodes interact with each other in a peer-to-peer manner and are not controlled by some kind of central server or group of servers. All these aspects ensure the decentralization of the blockchain network.
When a new set of transactions, packed in a block, appears in the network, a node broadcasts it to other nodes so that everyone within the network can verify the operation and update its own database after validation.
Each node operates based on a consensus mechanism used in the network that determines the node’s role and purpose for users to run it. Keep in mind that certain blockchain networks may have major differences in structure, so the general types described here can have varied responsibilities based on the underlying network.
In the crypto community, the term node is quite often used interchangeably with the term “full node”, but they are not the same. Full nodes are the nodes that essentially support the network, storing a copy of the blockchain and validating new transactions/blocks against the system’s consensus rules.
Theoretically, as long as even just one computer holds a full copy of the ledger, a blockchain network could be completely restored. The more full nodes are operating in the network, the more the network is considered decentralized and secured.
Full nodes may be divided into public and hidden. And the listening node is a node that is publicly visible and accessible. It acts as a communication bridge and data source for other nodes. Reliable listening nodes typically run 24/7 and have numerous established connections. Because of that, listening nodes may require more computational power and a better internet connection, especially compared to hidden full nodes.
When someone refers to the number of full nodes within a network, it implies the number of listening nodes. For example, there are currently over 15,000 public nodes running on the Bitcoin network as a way to secure its ecosystem. This number does not include hidden full nodes that may operate behind a firewall or are configured to not “listen” to other nodes.
Pruned full nodes
Usually, a full node refers to the one with the entire copy of the blockchain with every block and transaction since the first (genesis) block. Although full nodes provide more value to the network, this is not a requirement to be considered a full node.
A pruned full node is a node that saves hard disk space for its users by “pruning” older blocks in the blockchain and replacing them with newer blocks. This type of node will first download the entire blockchain from the beginning and then will cut it to a certain size limit. For example, if a node operator sets the size limit to 10 GB, then a full node would hold the most recent 10 GB worth of transactional data. Pruned full nodes have become popular in the Bitcoin network because the entire Bitcoin blockchain contains over 400 GB of data which may be too much for node operators.
Lightweight nodes or SPV client
Lightweight nodes, which are also known as light nodes or Simplified Payment Verification (SPV) clients on the Bitcoin network, do not participate in the process of verifying and validating transactions. Light nodes also do not hold the full copy of the blockchain. Instead, they only download block headers, saving users significant storage space and download time.
SPV can be used as a method to check whether or not some transactions were included in the block. Thus, light nodes rely on data provided by full nodes. Lightweight nodes are commonly used by cryptocurrency wallets to identify transactions.
Mining and validation nodes
Miners are considered nodes that try to prove they have completed their work to find new blocks. It’s important to emphasize that not all full nodes are miners, but miners need full nodes to accomplish their tasks. That is why miners may run their own full or light nodes to learn what transactions are requested and the current status of the blockchain network. If a miner works alone, they need to run a full node to share newly found blocks with the entire network. In mining pools, only the administrator of the pool is required to run a full node, other miners may use light nodes.
Validation nodes may refer to nodes used by validators in proof of stake networks. They act as full nodes with wallets where validators allocate their stake to participate in the staking process. In some networks, users may delegate tokens or vote for validators by sending funds to the validation node address. In order to remain eligible for staking rewards and providing block verification, validation nodes may need to have high uptime.
Authority nodes are used to achieve consensus in networks that are not fully decentralized. For example, those that use delegated proof of stake (DPoS) or proof of authority (PoA) consensus mechanisms. In these networks, either network creators, or the community decides how many nodes are needed to maintain the network and who will act as an authority node. Quite often, such networks may have an on-chain governance system to select authority nodes. The task of these nodes is the same as full or validation nodes in other networks.
Masternodes contain a full copy of the blockchain ledger but they cannot add blocks to a blockchain. They serve to validate specific protocol operations, including regulatory roles and verifying certain transactions. In order to run a masternode, a node operator has to lock a significant number of tokens, which is similar to validation nodes. Running a masternode empowers a node operator to earn a share of the network’s rewards.
DASH is an example of a network that uses masternodes. In this network, masternodes have more authority than regular full nodes, and are responsible for sending private (PrivateSend) and instant (InstantSend) transactions within the network. Dash’s masternodes also have a governance role by determining whether to approve or reject protocol upgrades.
Running a full node does not provide any financial rewards to users but empowers them to take advantage of many other opportunities. Full nodes do not need to trust others and allow users to be in total control of their funds. Full and light nodes come with wallets, allowing users to make cryptocurrency transactions with high privacy. In turn, full nodes contribute to the security of the entire network, helping blockchains achieve decentralization and providing other network participants with more opportunities.
With some nodes, users may both help the network and earn financial rewards but they require locking a certain amount of funds. However, regardless of the node you choose, keep in mind that running a node requires users to allocate certain storage space and computing power to maintain blockchain operations.
Disclaimer: For information purposes only. Not investment or financial advice. Seek professional advice. Digital assets involve risk. Do your own research.