What are miners on Ethereum?

Ethereum, like Bitcoin, currently uses a Proof-of-Work mining model. In proof-of-work, miners are decentralized computers that use their computing power to process and confirm transactions. In Ethereum, new transactions get added in "blocks" every 15 seconds. Miners are a built-in mechanism of the Ethereum blockchain and get paid in Ethereum's native cryptocurrency, ETH. When you pay for gas fees, the payment only guarantees your transaction to be processed. It does not guarantee that the transaction will succeed. This is because gas prices on Ethereum fluctuate widely. If there is a high level of activity on Ethereum - for example, a popular NFT collection is being released - gas prices will rise due to network congestion. In this case, the original gas fee you paid may no longer be high enough for miners to process and confirm the transaction.