The basics
Ethereum is one of the most popular public blockchains. It has its own cryptocurrency, called Ether (ETH) or Ethereum, and its own native programming language called Solidity to build and publish dApps (distributed applications) on the Ethereum blockchain.
Mainnet and Testnet
SettleMint supports, the Ethereum Mainnet, the Sepolia Testnet and the Holesky Testnet.
The Mainnet is the primary public Ethereum production blockchain, where actual-value transactions take place. Each transaction requires payment of a transaction fee, payable in the native coin ETH. The Testnet is an instance of the blockchain to be used for testing and experimentation. There are also coins used in the Testnet but they have no value, so there is no risk of real fund.
You can consider the Testnet as a prototype and the Mainnet as the official production blockchain. Or think of this as an analog to production versus staging servers.
Geth client
In order to participate in a blockchain, you need some form of client software that implements the features required to run a node. SettleMint uses Geth which is the official Ethereum client, written in the programming language Go, and fully open source. While there are other clients (like Parity), Geth can be seen as the de facto reference implementation for running an Ethereum node. It is the most widespread client with the biggest user base and variety of tooling for developers.
More information on Geth can be found on the official Geth website.
Consensus mechanism
Proof of Stake (PoS) is Ethereum's new consensus mechanism. In PoS, nodes are chosen to validate transactions and create new blocks based on the amount of Ether they hold and lock up as a stake. This means that the more Ether a node stakes, the higher its chances of being chosen to validate transactions and earn rewards for its work.
Unlike Proof of Work (PoW), which requires miners to perform computationally intensive tasks, PoS relies on the concept of "finality" – the idea that once a block is added to the blockchain, it is irreversible and has been "finalized." This makes the PoS consensus mechanism more energy-efficient than PoW.
Validators are chosen to participate in block validation based on a randomized algorithm that takes into account their staked Ether. This collateral can be slashed if they misbehave or act maliciously. The PoS consensus mechanism is currently being implemented on the Ethereum mainnet chain as well as Goereli testnet.
More information on the consensus mechanism can be found on the official Ethereum website.