On top of a blockchain, the Lightning Network is a “second layer” payment technology. It has been hailed as a solution to the scalability issue with Bitcoin because it is built to facilitate quick, scalable transactions between and among participating nodes. Normally, transactions take place on the blockchain, but Lightning allows for off-chain transactions.
The initial purpose of the Lightning Network was to ease the load on the Bitcoin network and minimize transaction fees. Utilizing the Lightning Network has expenses, and detractors assert that this scaling method is also vulnerable to attacks. Additionally, they are supposed to be online all the time, which might be difficult.