Every blockchain has a mainnet. The mainnet is the blockchain that actually carries out real-world transactions and events for the public. This is different from a testnet, which is used to test out those transactions and events before putting them into production.
There are four different types of testnets that Alchemy supports.
Rinkeby is a proof-of-authority blockchain that uses the Clique PoA consensus protocol, and is only supported by Geth. This testnet is immune to spam attacks since the Ether supply is controlled by trusted parties and has to be requested from a faucet, not mined.
Note: Rinkeby doesn't fully reproduce the current production environment since it uses PoA.
Average block time: 15 seconds.
Explorer: https://rinkeby.etherscan.io/β
Check out more info about Rinkeby on the website.
Goerli is a proof-of-authority blockchain, supported by multiple clients. This testnet has the goal of being both widely usable across all client implementations supporting Clique Proof of Authority (PoA) engine and robust enough to guarantee consistent availability and high reliability.
Average block time: 15 seconds.
Status Dashboard:
Block Explorer:
Faucets:
Check out more info about Goerli on the GitHub.
Kovan is a proof-of-authority blockchain, started by the Parity team and supported by Parity only. Ether canβt be mined; it has to be requested from the faucet. This testnet is known for being immune to spam attacks.
Note: Kovan doesn't fully reproduce the current production environment since it uses PoA.
Explorer: https://kovan.etherscan.io/β
Check out more info about Kovan on the GitHub.
Ropsten is a proof-of-work blockchain that most closely resembles the current Ethereum production environment, it is supported by Geth and Parity.
Note: Ropsten is not immune to spam attacks so it is less stable.
You can easily mine faux-Ether or request it from a faucet:
Faucets
Explorer: https://ropsten.etherscan.io/β
Check out more info about Ropsten on the GitHub.