Nodes are devices connected to a blockchain network that keep a copy of blockchain records and help the network run smoothly and securely. Here’s what you’ll learn:
A node is a device or group of devices, such as a computer or mobile phone, connected to the blockchain network. Each node has a copy of either the entire blockchain ledger or some parts of it, which they use to carry out their tasks. They also relay correct transaction information to other nodes, ensuring that every device has current and correct details in its record.
Since each node maintains a copy of the blockchain, the network continues to operate securely even if some nodes are compromised by security attacks, software errors, physical damage, or power outages.
The different nodes in a network are responsible for keeping it running correctly. There are two main types: Full Nodes and Light Nodes. Let's break down what each type does in simpler terms, making it easier to understand their roles and importance.
Full nodes are the most powerful nodes in the network. They maintain a complete copy of the blockchain ledger, which includes every payment, transfer, or any transaction ever recorded. All this data allows them to do their job of validating each transaction according to the blockchain’s rules and adding it to the blockchain record.
By maintaining the full history and rules of the blockchain, Full Nodes provide security and prevent centralization of control. They act as auditors and make sure that the blockchain is trustworthy and secure. Without them, it would be easier to tamper with data or cheat with transactions.
Validate Transactions
They look at each transaction carefully to make sure everything is correct. For example, if you’re buying an NFT from a marketplace, nodes check if your wallet address has enough money to pay for it and if the recipient address is correct. They check the entire history of your wallet to make sure that the money you’re using to buy the NFT hasn’t already been used in another transaction. Once they have verified that everything is correct, they officially transfer ownership of the NFT to you and record the transaction on the blockchain
Maintain Consensus
To add new data to the blockchain, the nodes need to follow blockchain rules to reach consensus, or agree on the validity of new transactions. Depending on the blockchain, different consensus mechanisms may be used to process the transactions. Achieving consensus prevents fraud and ensures all nodes have the same record of the state and history of the blockchain ledger.
Update the Network
Nodes help protect the blockchain from attacks and ensure it runs smoothly by updating the software and protocols as needed. They vote on proposed updates or changes, such as improvements to the protocol or new features. A majority of network participants must agree to these changes before they can be implemented.
Light or "lite" nodes don’t keep a full copy of the blockchain; instead, they just keep enough information necessary to verify the transactions relevant to them. They rely on full nodes to access more comprehensive information about the state of the blockchain. Compared to full nodes, they consume less energy and resources.
Light Nodes allow you to participate in the network even if you only have simple everyday devices such as your mobile phone. This makes blockchain more practical for everyday applications, for anyone, anywhere, and at any time.
Make Quick Checks
Light Nodes can quickly check if a transaction is valid by asking other nodes for proof of this particular transaction, without needing the full blockchain data.
Scale the Network
By not requiring as much data and computing power, Light Nodes allow more people to participate in the blockchain, even if they don’t have powerful computers or lots of data storage.
Both Full Nodes and Light Nodes play vital roles in the blockchain network. Full Nodes keep records of the blockchain's entire history and rules, while Light Nodes do quick transactions and help make blockchain technology accessible to more people.
Blockchains also use specialized nodes which have unique functions, such as:
In a network using the Proof-of-Work consensus mechanism, nodes that solve mathematical puzzles to mine new blocks and add them to the blockchain are called mining nodes. A mining node may be just one individual miner or a group of miners working together to make up a mining pool.
In a network using Proof-of-Stake, a node that locks up crypto to validate new blocks and add them to the blockchain is called a validator node. Validators need to stake a minimum amount of crypto for the chance to be selected by the system to add the next block. They receive compensation for their work from a portion of the network transaction fees.
Archive nodes are special types of full nodes that keep not only a record of the whole blockchain but also a record of the complete history of the blockchain.
Blockchain nodes work together to support the network by verifying transactions, contributing to consensus, keeping the network secure, and maintaining an up-to-date and accurate record of the blockchain. They ensure that transactions are processed securely and accurately while maintaining the health and growth of the system.
Learn more about blockchain nodes through our blockchain architecture course!
