Before a project launches on the Ethereum blockchain (or before changes are made to the blockchain itself), a version is deployed to an Ethereum Test Network (“testnet”), which simulates Ethereum — this gives developers, the community, and you a chance to kick the tires before real assets are involved.
Ether and tokens on a testnet are easy to obtain, and carry no real-world value — still, it can be fun to own 10,000 Ether or a trillion tokens on a testnet.
There are three testnets currently in use, and each behaves similarly to the production blockchain (where your real Ether and tokens reside). Developers may have a personal preference or favorite testnet, and projects typically develop on only one of them.
- Ropsten: A proof-of-work blockchain that most closely resembles Ethereum; you can easily mine faux-Ether.
- Kovan: A proof-of-authority blockchain, started by the Parity team. Ether can’t be mined; it has to be requested.
- Rinkeby: A proof-of-authority blockchain, started by the Geth team. Ether can’t be mined; it has to be requested.
Connecting to a testnet
Ethereum addresses & private keys that work on Ethereum, work on each testnet — be extremely careful not to send Ether or tokens on the Ethereum main-net to a testnet address, or you will lose your assets.
Before proceeding, Compound recommends creating a new wallet specifically for use on testnets; you’ll never accidentally send Ether, if you don’t have Ether.
Using MetaMask to send Ether and tokens on a testnet is straightforward; in the top-left of MetaMask, you can select an Ethereum network.
Switch from the Main Ethereum Network to Rinkeby (or other testnet) and you should see your balances and transaction history update, to reflect the network you’ve selected.
Now, when you create a transaction using MetaMask, it will be transmitted to the network you’ve selected.
MyEtherWallet & MyCrypto
MyEtherWallet and MyCrypto similarly allows you to select an alternate network, in the top right of the screen. When you do so, all transactions, and contract calls are conducted on the network that you’ve chosen.
It’s time to load up your new account with faucet Ether.
The Kovan Faucet requires you to provide your Github account credentials to Parity, and allows you to request Kovan Ether once every 24 hours.
The Rinkeby Faucet requires that you make a social media post including your address on either Facebook, Twitter or Google Plus. Once you do so, put the direct link to that post in the input box and select
18.75 Ethers / 3 days from the dropdown on the right.