Bitcoin scalability problem

These modifications can be to either the network, in which case a fork is required, or to individual node software (such as Bitcoin Core).

The Lightning Network (LN) is a protocol that aims to improve bitcoin's scalability and speed without sacrificing trustless operation.

[9] The Lightning Network requires putting a funding transaction on the blockchain to open a payment channel.

On 15 March 2018, Lightning Labs released the beta version of its lnd Lightning Network implementation for bitcoin mainnet, and on 28 March 2018, ACINQ released a mainnet beta of its eclair implementation and desktop application.

In January 2019 the online retailer Bitrefill announced that it receives more payments in Bitcoin via the lightning network than any other cryptocurrency they accept.

Number of transactions per month, on a logarithmic scale
A Lightning Network overview