Launched in 2015, Ethereum is a programmable proof-of-work protocol that enables developers to build and deploy decentralized applications.
Ethereum has a native token called Ether (ETH) and is programmable, meaning that developers can use it to build decentralized applications (dApps).
Types of Ethereum Nodes
There are three classes of nodes in Ethereum: Archival, Full and Light.
Archival nodes store all blockchain data, similar to Full nodes, while building an archive of historical blockchain states. They are useful for querying the full chain state at any given block height.
Full nodes, most commonly implemented in Geth (written in Go), participate in consensus by ensuring that blocks and the transactions contained within them are valid. Running a Full Geth node lets you transfer funds between addresses, create contracts, explore block history, and much more. Full nodes store all relevant blockchain data and can serve data upon request.
Light nodes do not verify every block or transaction nor download the whole blockchain, so may not have a copy of the current blockchain state. They enable pushing transactions into the blockchain, and are advantageous in that they can get up and running much more quickly, use less memory, and don’t require as much storage.