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What is Bitcoin’s Lightning Network?

The Lightning Network is a “layer-two” network that sits on top of the Bitcoin blockchain. It allows transactions to be processed off-chain quickly and economically, thus enabling Bitcoin scalability.
Lighting Website Thumbnail
Why is it needed?
Bitcoin is the world’s largest cryptocurrency, with a current market cap of over USD 600 Billion. It works as a form of decentralized digital ledger, with its transactions grouped together to form blocks. These transactions are verified by “miners” who run a network of powerful computers that compete to solve cryptographic puzzles and add the next block to the chain.



Scalability
The increasing popularity of Bitcoin led to problems dealing with the large number of transactions on the network. Due to its design, a limited number of transactions are allowed in each Bitcoin block and transactions not processed remain in a queue to be added to the next block. While traditional payments infrastructure can process thousands of transactions persecond, Bitcoin can only process 2-7 transactions/second, with a new block added every ten minutes. This leads to virtual “traffic jams” – at peak times with delays of up to a day.



Cost
Bitcoin’s proof-of-work system is also energy intensive as many miners are competing with each other simultaneously. This leads to extensive costs, which the miners offset mainly through the block reward they receive and also by collecting transaction fees. Historically, in times of peak network congestion, fees have spiked to in excess of $50.

The Lightning Network addresses these problems.



How Does Lightning Network Work?
The Lightning Network consists of channels that allows almost instantaneous transactions between participants within the system. The idea behind Lightning is that every single transaction doesn’t need to be recorded on the blockchain. Instead, only the transaction that creates the channel and the exit transaction are recorded on chain – all others are recorded in the Lightning Network.

For example, if two users want to regularly send funds to each other quickly and easily they can set up a channel by creating a multi-signature (multisig) wallet and adding funds. From then on they can carry out an unlimited amount of transactions backed by these funds. Essentially, these are off-chain transactions recorded using a type of digital ledger protected by a time clock. Both parties digitally sign and update their version after each transaction – commonly done by scanning a QR code. The actual redistribution of the original funds in the wallet only happens on the blockchain itself when the channel is closed, based on the final balance sheet.

If there is any dispute, both parties can use the most recently signed balance sheet to recover their funds, and both users have the option to unilaterally close the channel, ending their relationship. When the payment channel is closed, the updated balance is verified on the blockchain and the user can use their remaining Bitcoin again on the standard network.

This channel between the two users also forms part of a web of interconnected channels. Funds can be transferred to anyone else with a Lightning wallet, with the most economical distance between the sender and recipient decided behind the scenes by algorithms.



Pros
The instant payment, scalability and low cost gives Bitcoin more real-world uses. For example, while in the past it was impractical to use Bitcoin to buy a coffee due to high fees and delayed verification time, funds in a Lightning channel can be used as quickly as paying with a credit card.
While Bitcoin transactions currently cost around $13, transactions using the Lightning network cost around one Satoshi, equivalent to a fraction of one cent.
Lighting can be used for smaller payments – the minimum is 0.00000001 BTC, or one Satoshi.


Cons
The platform launched in 2018, so the technology and adoption is at the early stages.
Opening and closing a channel involves Bitcoin transaction fees. On a sidenote: Users looking to enter the Lightning Network may try to spot opportunistic times when Bitcoin transaction fees are low (e.g. on weekends).
Transactions can only be made when all parties involved are online.