Payment or state channels are one of the more established blockchain scalability solutions. The idea is to use side channels or chains for processing transactions off the main chain. Once transactions on the side chain are processed and the state of the channel is finalized, it is written back on the main blockchain, as shown in the following diagram:
In this way, a lot of the transaction processing load is outsourced to a faster side chain, thus minimizing the amount of total validation effort by miners.
Here's a useful example to clarify this idea. Imagine that two friends go to a bar and open a tab. In this way, ...