Usually before a project is released to the public on the Ethereum blockchain or before “edits” are made to the blockchain, a version of the proposed project is deployed to an Ethereum Test Network hence its called a “testnet”. The idea behind this is that it simulates Ethereum and this gives developers and the community as a whole a chance to beta-test the project before real assets are involved. Coins such as Ether and tokens on the testnet are pretty easy to obtain, and hence carry no real-world value.
There are 3 popular testnets currently being used, and each of these actually behaves in a similar manner to the production blockchain (this is where your real Ether and tokens reside).Some developers may have a personal preference or favorite testnet to use for their projetcs. And projects typically developed and tested on only one of them.
- A proof-of-work Ropsten is a blockchain that closely resembles Ethereum.
- Kovan is a proof-of-authority blockchain, which was started by the Parity team.
- Rinkeby is a proof-of-authority blockchain, which was started by the Geth team.
Precautions when connecting to a testnet
Any Ethereum addresses or private keys that is capable of working on the Ethereum blockchain, also works on each testnet . Hence, you will have tobe very careful.You cannot send Ether or tokens on the Ethereum main-net to a testnet address, or you will lose your assets.