Testnet versus mainnet: do you need to buy test coins?

While trying a new service, you may be asked to switch your wallet from mainnet to a testnet. Testnets are separate networks where developers and users check functionality. Even if addresses look the same, balances and transaction histories are not shared with mainnet.

Different network roles

• Mainnet: The operational network, where asset transfers and contract execution can affect real economic value.
• Testnet: A public network for testing features and changes. It may have a specific purpose or support period.
• Local development network: A test network a developer runs in their own environment.
• Faucet: A service distributing coins needed for testing. It may require a login or impose limits to prevent abuse.

Test coins are for testing and are not the same assets as mainnet coins. Sharing a name or ticker does not guarantee exchange value.

Before testing

1. Check the currently supported testnet in the project's official documentation.
2. Match the network name, chain ID and RPC URL.
3. Use faucets and explorers linked from official guidance.
4. Keep a test wallet separate from wallets holding important assets.

Testnets still use wallet signatures and keys. Do not enter a recovery phrase into a website because “it's only a test”. Adding a network to a wallet and handing over a private key are entirely different actions.

Testing does not guarantee rewards

Making many test transactions does not automatically create an entitlement to an airdrop. There may be no reward plan, criteria may change or certain activities may not count.

Testnets can be reset or retired. Be wary of claims presenting test assets as real assets, or requests for payment to guarantee a reward. Prefer current official network documentation over old settings in a blog post.

References

ethereum.org