What is a blockchain testnet?

A testnet is an alternative blockchain network that serves as a sandbox environment for developers to test their code before rolling out new updates to the mainnet. Zoom on testnets and their importance with the example of the Ethereum blockchain.

What is a testnet?

A testnetabbreviation of “test network”, and translatable into “test network” in French, is a version almost identical to an active blockchain (mainnet), but only dedicated to carrying out tests.

Indeed, such a network aims to test new functionalities of a blockchain without cost or risksince the underlying cryptocurrency of this network has no real economic value.

Thus, a testnet uses own cryptocurrencya copy of the original asset, but not having no value. Using a testnet’s cryptocurrency has no impact on the public blockchain, since a testnet is completely isolated from the original chain : it is impossible to transfer cryptocurrencies from a testnet to a mainnet and vice versa.

The code of a blockchain can therefore be tested with the testnet without affecting the active network that hosts the smart contracts and decentralized applications. In addition, on a testnet, any user can retrieve the underlying cryptocurrency at no additional cost, again for testing purposes.

Generally, it is enough to click on a button from a dedicated interface to recover a random amount of this cryptocurrency. This is one of the reasons why testnet cryptocurrencies are worthless.

A testnet is therefore an environment that allows test new updates before deploying them on the public blockchain. The developers generally carry out batteries of tests to detect possible errors in the codebugs, and in general to check that everything is working correctly.

A product should always be extensively tested before going into production to certify its proper functioning, in any industry. The cryptocurrency industry is no exception and the testnet is the medium through which testing is done.

An update directly deployed on a public blockchain, without having tested it on a testnet, could have dramatic consequences on millions of users in the event that there are errors in the codeso it is the responsibility of the developers to ensure that this does not happen through the use of testnets beforehand.

Finally, once the update has been thoroughly tested on a testnet, it can finally be implemented on the mainnet, usually not before a vote of network participants who approves of the latter.

The Ropsten testnet of the Ethereum blockchain

A concrete example of a testnet is Ropsten, an Ethereum blockchain testnet. Launched in November 2016, it is the oldest Ethereum testnet, but there are others like the Sepolia or Goerli testnet. A blockchain does not necessarily have only one test environment.

The Ropsten testnet is used by Ethereum developers to test protocol updates before deploying them on the Ethereum mainnet.

This testnet is almost identical to the public Ethereum blockchain and, being a testnet, the developers have no no need to worry about transaction implications and application testing costs.

Ropsten thus allows developers to access an Ethereum test environment in which errors and failures have only very negligible consequences.

As of this writing, the Ropsten testnet is used to testing consensus Ethereum blockchain migration Proof of Work to a consensus Proof of Stake. This famous and highly anticipated update, also called The Merge, presents a real technical challenge.

The new version of Ethereum will reduce the energy consumption of the network and facilitate the participation of users in securing the network, which will consequently increase the level of decentralization, but migrating from Consensus PoS to Consensus PoW is a very complex operation.

Ethereum being to date the main network used for decentralized finance and non-fungible tokens, the slightest error that would not be detected before the migration could prove fatal for the cryptocurrency ecosystem as a whole.

This is how the Ropsten testnet allows developers tocarry out a whole battery of absolutely necessary tests before the deployment of this migration on the Ethereum public blockchain.

👉 Learn more about the Ethereum blockchain

The complement of the testnet, the mainnet

A testnet has no interest without its complement, the mainnet. All scans conducted on a blockchain testnet are for the purpose of deploying the upgrade to the mainnet.

The latter is a network on which real transactions take place and on which the native cryptocurrency has real economic value. A mainnet is the main and functional blockchain of an ecosystem.

Thus, the tests carried out on the testnet make it possible to get rid of errors, bugs and then deploy a functional updatebug free on the mainnet.

One of the best-known mainnets in the cryptocurrency industry is Ethereum mainnetwhich has been updated since 2015 by hard forks such as the Byzantium (2017), Constantinople (2019), Istanbul (2019) or London (2021) forks.

All of these Ethereum protocol upgrades first is being tested on one of the Ethereum testnets so that they are operational and without bugs.

👉 Find all our guides to learn more about the cryptocurrency ecosystem

Newsletter 🍞

Get a crypto news recap every Sunday 👌 And that’s it.

Leave a Reply

Your email address will not be published.