What is the Sepolia testnet?
Sepolia is a proof-of-work (PoW) testnet where dApp developers can test their applications. What differentiates Sepolia from other Ethereum testnets is that most of its PoW validators are public validators. Combined with Sepolia being a testnet, this creates the chance that validators will stop validating and the chain will fail to finalize, making Sepolia one of the best testnets to see how decentralized applications will perform under the harshest conditions.
To begin using Sepolia, you must first head to the Sepolia Faucet to collect Sepolia ETH, the testnet’s token. Once the testnet ETH is sent to your wallet, you can begin testing your nodes and smart contracts on Sepolia.
Note: Alchemy does not support the Sepolia testnet. For a complete list of testnets supported by Alchemy, refer to our official documentation.
What is the Sepolia Testnet?
Sepolia is a PoW tesnet created in October 2021 by Ethereum core developers and maintained ever since. After the Ropsten testnet reaches a Terminal Total Difficulty (TTD) of 50000000000000000 and transitions to proof-of-stake, which is expected to occur between June 8th and June 9th, 2022, Sepolia and the Goerli testnet will move from a proof-of-work to a proof-of-stake consensus mechanism to mimic the Ethereum mainnet.
According to Ethereum core developer, Tim Beiko, once Ropsten, Goerli and Sepolia have forked and stabilized the development team will be able to finalize the date to complete the Ethereum Merge.
Testnets are blockchains designed to mimic the operating environment of a ‘mainnet’ but exist on a separate ledger. These shadow forks enable core developers to test the merge, and help application developers test how their apps will perform during and after the Ethereum mainnet merge without financial consequences by testing in Ethereum’s production environment.
How is Sepolia different from other testnets?
The difference between Sepolia and other Ethereum testnets is that Sepolia is a closed, permissioned testnet in contrast to public testnets like Goerli.
These validators who have not undergone any background check or capability testing by network participants, could possibly fail to have the necessary hardware and software to stay connected to the testnet at all times, and hence cause the chain to fail to finalize.
Over the long-term future the Ethereum team plans on only maintaining the Goerli testnet and maintaining the Sepolia testnet, who’s chain ID is 11155111.
How to get Sepolia testnet ETH?
Sepolia ETH can be obtained from a Sepolia testnet faucet, that allows anyone to send a small amount of fake Sepolia ETH to their wallet. Sepolia ETH is the currency used to pay to complete transactions on the Sepolia testnet, similar to how ETH is used to pay for computation on the Ethereum’s mainnet which is also a Proof-of-Work chain before the merge.
- Head to the Sepolia FaucETH - https://faucet.sepolia.dev
- Enter your wallet address or ENS name into the box.
- Fill out the captcha
- Click ‘Request funds’
A popup will display ‘Transaction sent’ with the amount of Sepolia ETH deposited to your wallet.
With your Sepolia ETH, you can now begin running smart contracts on the Sepolia testnet.
To view the date and time, the transaction fee, the gas burnt, and other transaction details, you can look up your transaction hash on Otterscan, a Sepolia testnet block explorer.
Additional Reading and Resources on the Sepolia Testnet
The best resources about the Sepolia testnet and upcoming Ethereum testnet changes include Ethereum’s official blog, Tim Beiko’s AllCoreDevs Updates, the Week in Ethereum Substack newsletter, and this big list of resources about the Merge.
With changes happening to test the Ethereum Merge, it’s important to follow the right sources to ensure you have the most up to date information about the Sepolia testnet and the upcoming testnet merges.