How a faucet works
You paste your wallet address, pass a check such as a captcha or login, and the faucet sends tokens from its own balance on the testnet.[1]
ethereum.org describes most faucets as web apps where you enter an address and request ETH to be sent to it. The faucet then signs a normal transaction from its own wallet, so the tokens arrive like any other transfer and show up in a block explorer for that testnet.[1]
Delivery is not instant. Alchemy's faucet FAQ says delays happen when the testnet is congested or when the gas the faucet set for its transaction is low compared with other pending transactions.[3]
Why faucets have limits
Testnet tokens are free, so faucets limit amounts, add cooldowns or require a small mainnet balance to keep bots from draining them.
Alchemy's Sepolia faucet sends 0.1 ETH per request, once every 24 hours, with the limit applied per address. To qualify, the address needs at least 0.001 ETH on Ethereum mainnet, enough real mainnet transaction history, and a low existing Sepolia balance.[3]
The mainnet balance is only checked, not spent. A new wallet with no mainnet history will usually fail these checks even if it holds the minimum balance, so developers often use a wallet they already transact with.[3]
Risks and scams
A real faucet only needs your public address. ethereum.org's security guide says no legitimate service or website will ever ask for your seed phrase or private keys, so a faucet that asks for them is a scam.[2]
Which testnet to request
ethereum.org names two public testnets that client teams maintain. Sepolia is the recommended default for app and contract development. Hoodi is for protocol developers and stakers testing validators and upgrades. Holesky was deprecated in September 2025.[1]
ethereum.org notes that Sepolia runs on a permissioned validator set controlled by client and testing teams.[1]
Ephemery is a third option for short tests: its state resets to genesis every 28 days, so anything you deploy there disappears on the next reset.[1]
Each network needs its own faucet. The chainid.network entry for Sepolia (chain ID 11155111) lists a Sepolia faucet, and the Hoodi entry (chain ID 560048) lists faucet.hoodi.ethpandaops.io and hoodi-faucet.pk910.de.[5]
L2 testnets have separate faucets too. ethereum.org lists faucets for Arbitrum Sepolia, OP Sepolia and Starknet Sepolia, and Base points developers to its own Base Sepolia faucets for test ETH and test USDC, with Circle's faucet as a second source of test USDC.[4]
Example: how far one faucet claim goes
The numbers here are illustrative, not a quote of current testnet gas prices. Assume one claim of 0.1 ETH, a testnet gas price of 10 gwei, and a contract deployment that uses 1,500,000 gas.
A plain ETH transfer uses 21,000 gas. At 10 gwei: 21,000 × 10 = 210,000 gwei = 0.00021 ETH. One claim covers 0.1 ÷ 0.00021 = 476 transfers, with a small remainder.[6]
The deployment costs 1,500,000 × 10 = 15,000,000 gwei = 0.015 ETH. One claim covers 0.1 ÷ 0.015 = 6 deployments (0.09 ETH), leaving 0.01 ETH for about 47 transfers.[6]
If a deploy script runs out of gas partway through, the gas it used is still charged, so a few failed attempts can use up a claim faster than the math above suggests.[6]
Common mistakes
Requesting tokens on the wrong network is the most common problem. Sepolia ETH and Base Sepolia ETH are separate balances on separate chains, even though the address is the same, so check that your wallet is on the chain the faucet paid out on.[4]
Another mistake is holding a large testnet balance and asking for more. Alchemy's criteria say wallets with a significant amount of testnet tokens are not eligible for additional claims.[3]
The Bottom Line
Use a faucet to get free tokens for testing, and share nothing but your address.
Educational content, not financial advice.