What Is the Bitcoin Lightning Network? How It Works
The Lightning Network is bitcoin's second layer: a network of computers that send bitcoin to each other without writing every payment to the blockchain. Two Lightning nodes open a channel and pay each other through it as often as they like. Payments hop across channels from node to node, so you can pay anyone on the network, usually in under a second, for a fee that's often a tenth of a percent or less. Only a channel's opening and closing are written to the blockchain.
- It's real bitcoin. Lightning isn't a separate coin. Every payment moves actual bitcoin, counted in sats.
- It's fast. A payment from New York to London can cross in about 70 milliseconds, and most settle within a second.
- It's cheap. About half a cent on a $5 payment, and no fee at all over a direct channel.
- It's safe. The newest balance can always be written to the blockchain, and a node that cheats can lose everything in the channel.
- It's proven. Lightning has been up and running on bitcoin's main network since 2018.
Why Bitcoin Needs the Lightning Network
Bitcoin is a ledger kept by thousands of computers around the world. Every payment is written into a block, and about every ten minutes a new block is stacked on top of the last one. To change an old payment, you'd have to redo its block and every block on top of it. That's why bitcoin is so secure. It's also why it's slow: to be really sure a payment is final, people wait for six blocks, about an hour.
For big transfers, that's fine. If you're sending a billion dollars, waiting an hour is no problem. But each block has limited space: only so many payments fit in one, and the whole world shares about half a million transactions a day. So every payment bids for a place in the next block. When it gets busy, the fee for a single payment can jump from under a dollar to $50 or more, without warning. Fine for a billion dollars; not so fine for a coffee. More: The Problem With Bitcoin Payments.
Developers saw this coming, and were looking for a way to scale bitcoin as early as 2010. In 2015, Joseph Poon and Thaddeus Dryja published the answer, "The Bitcoin Lightning Network: Scalable Off-Chain Instant Payments". The first Lightning software ready for bitcoin's main network, lnd 0.4-beta, came out on March 15, 2018, and Lightning has been up and running ever since. More: The Lightning Proposal.
How Does the Lightning Network Work?
The big idea: don't write every payment to the blockchain. Lightning writes to the chain only twice for each channel:
- When the channel opens. You lock some bitcoin into the blockchain, and from then on moving it takes both nodes' signatures.
- In between, nothing. The two nodes sign a new balance for every payment. This happens off the chain, as fast as two computers can talk to each other.
- When the channel closes. Either node can close it at any time, and the latest balance is written to the blockchain. Each side gets its share.
What Is a Lightning Channel?
A Lightning node is a computer that holds bitcoin and stays online. A channel is a shared balance between two nodes. To open one, you lock some bitcoin into the blockchain, say 1,000,000 sats. A million sats is 0.01 bitcoin (see What Is a Satoshi?).
What Is Channel Balance?
A channel's balance is split between its two sides:
- The sats on your side are what you can send.
- The sats on the other side are what you can receive.
When you pay the other node, the balance simply slides across. Both nodes sign the new split, and nothing is written to the blockchain. The total never changes:
| What happens | Your side | Their side | Total |
|---|---|---|---|
| You open the channel | 1,000,000 sats | 0 | 1,000,000 |
| You pay 100,000 sats | 900,000 sats | 100,000 sats | 1,000,000 |
| You pay 100,000 sats again | 800,000 sats | 200,000 sats | 1,000,000 |
| They pay you 50,000 sats | 850,000 sats | 150,000 sats | 1,000,000 |
Why a New Channel Can't Receive
A channel you open yourself starts with every sat on your side. You can send, but you can't receive anything, because the far side is empty. The room to receive is called inbound liquidity, and it's why a wallet that runs its own node needs a channel from someone else before it can be paid.
Here's a real one. We ordered a million sats of receiving room for our own Alby Hub node from Megalith's LSP, for 18,507 sats, and the channel opened in about two seconds. It opened with the sats on Megalith's side, so we could receive 989,340 sats and spend nothing. When a payment came in, those sats moved to our side, and then we could spend them. More: Do I Need to Rebalance My Channels?
How Do Payments Hop Across the Network?
You don't need a channel to everyone you pay. To pay someone you're not connected to, your payment goes to a node you are connected to, which passes it on until it arrives. Each channel along the way shifts by the same amount, so the nodes in the middle neither gain nor lose, apart from a small fee.
Today there are thousands of nodes all over the world. Big, well-connected nodes like The Megalith Node tie them together, so a single good channel can reach almost anyone. More: How Lightning Scales Bitcoin.
How Much Do Lightning Payments Cost?
- Over a direct channel: no fee at all.
- Across other nodes: each node that passes a payment on keeps a small fee. About 1,000 parts per million (0.1%) is considered reasonable, which is about half a cent on a $5 payment. Nodes can also charge a tiny base fee, typically around 1 sat.
- Opening and closing a channel: these two steps are bitcoin transactions, so each pays an ordinary on-chain fee.
More: How Much Does It Cost To Send A Lightning Payment?
How Fast Is the Lightning Network?
A payment moves as fast as two computers can talk to each other: about 25 milliseconds from New York to Chicago, and about 70 milliseconds from New York to London. Even to the other side of the world, under good network conditions, a payment should settle within one second.
Is the Lightning Network Safe?
If payments aren't on the blockchain, what stops someone from cheating? Three things:
- Either node can close the channel at any time, and the latest balance is written to the blockchain. Each side gets its share.
- Old balances are cancelled. When the nodes sign a new balance, the old one stops being safe to use. A node that tries to close with an old balance has to wait before it can touch those sats, typically between about one day and two weeks. In that time the other node can prove the balance is old and take everything in the channel. If you're offline, a watchtower does this for you.
- A payment across several nodes is locked to a secret that only the person you're paying knows. Each hop gets paid only when that secret comes back (a hash time-locked contract), so the whole route completes or none of it does. No node in the middle can keep your money.
It's private too: each node on a route sees only the node before it and the node after it. More: How Private Is Lightning?
Lightning vs On-Chain Bitcoin
| On-chain bitcoin | Lightning Network | |
|---|---|---|
| What's recorded on the blockchain | Every payment | Only a channel's opening and closing |
| Time | About 10 minutes a block, about an hour for six blocks | Usually under a second |
| Fee | Depends on how busy blocks are: under a dollar, up to $50 or more | Often 0.1% or less; none over a direct channel |
| Smallest payment worth sending | Limited by the fee | A single sat |
| To get paid | A bitcoin address | A Lightning invoice or Lightning Address, and room to receive |
| Best for | Large transfers | Everyday payments |
Bitcoin is the base layer: slow, permanent and secure. Lightning is the fast layer on top, for everyday payments.
How to Use the Lightning Network: Three Ways to Start
From the hardest to the easiest:
- Run your own node, the full way. Our guide walks you through it step by step: a dedicated Linux computer with two mirrored drives, Bitcoin Core, LND and Tor in Docker, backups and a watchtower. It's highly technical, and you'll learn how every part of Lightning works. Start at Should I Run a Lightning Node? and Set Up a Lightning Node.
- Your own node, the easy way: Alby Hub. It's free, runs on your own computer, and you use it in a web browser. To receive payments it needs a channel, and it suggests Megalith as your channel partner. It's also a great fit for merchants, with tools for online shops and point of sale.
- The easiest: Rizful. A free Lightning wallet in your web browser or on your phone. Sign up and you get a Lightning Address anyone can pay, with no node or channels to manage.
We tested more of them with real bitcoin in The Best Bitcoin Lightning Wallets.
Taking payments on a website or in an app? OpenReceive is the safe way to receive bitcoin and stablecoin payments for websites and apps, and the payments land in your own wallet.
How to Send and Receive Bitcoin on Lightning
- To send: open your Lightning wallet, scan or paste a Lightning invoice or type a Lightning Address, and confirm.
- To receive: give the sender your Lightning Address, or create an invoice for the amount and share it.
Lightning Network FAQ
Is Bitcoin Lightning the Same as Bitcoin?
Yes. Lightning is a way of moving bitcoin, not a different coin. A channel holds real bitcoin, locked on the blockchain, and closing the channel puts each side's share back there.
Do I Need to Run a Node to Use Lightning?
No. A wallet like Rizful gets you sending and receiving with no node or channels to manage. Run your own node if you want to choose your own channels and channel partners.
What Is a Lightning Invoice?
A one-time payment request from the person being paid. Their wallet creates it, you scan or paste it, and your wallet pays it. A Lightning Address looks like an email address and works for any number of payments: the sender's wallet asks it for a fresh invoice each time.
Can a Lightning Payment Fail?
Yes, if no route can carry it, for example when the channels along the way don't have enough on the right side. A payment across several nodes completes in full or not at all, so a failed one leaves your sats with you, and you can try again.
When Did the Lightning Network Start?
Joseph Poon and Thaddeus Dryja published the idea in 2015. The first Lightning software for bitcoin's main network, lnd 0.4-beta, came out on March 15, 2018, and the network has been running since then.
Is the Lightning Network Decentralized?
No company runs it. It's made of independent nodes joined by their channels, and anyone can run one. Big, well-connected nodes carry many of the payments, but either side of a channel can close it at any time.
How Big Is the Lightning Network?
Thousands of nodes. The trackers disagree on the count: 1ml.com showed 5,563 nodes on November 4, 2026, and mempool.space's last figures, from May 2026, showed 17,437.
Does Cash App Use the Lightning Network?
Yes. Cash App (US only, and not in New York) can pay Lightning invoices and has its own Lightning Address. We tested it in The Best Bitcoin Lightning Wallets.