Sidechains, also known as secondary blockchains, are separate blockchain networks connected to the main blockchain (mainnet) via a two-way peg. This connection enables the transfer of tokens and digital assets from the mainnet to the sidechain (and vice versa) at a predetermined rate.
In return, this empowers individual projects to expand their ecosystem without a heavy reliance on the mainnet. In practise, sidechains enable developers to test features and use cases that are not normally available on the mainnet. This is because sidechains can be programmed with certain optimisations in mind, such as making transactions faster, cheaper, and more accessible.
Sidechains also have a variety of real-world applications. For example, Rootstock, a Bitcoin sidechain, was created as a digital ledger to run smart contracts more efficiently. On the other hand, the sidechains on the Ethereum network are Loom Network and SKALE.
