Lightning is a network of payment channels on top of Bitcoin. Payments settle in seconds for tiny fees without a new on-chain transaction each time.
Why Lightning exists
On-chain Bitcoin settles about every 10 minutes and block space is limited. That's great for final settlement but slow and costly for buying a coffee. Lightning moves most payments off-chain, while still using Bitcoin's security.
Channels
Two people lock bitcoin into a shared on-chain output: a payment channel. They can then pay each other back and forth instantly by signing new balance updates, without touching the blockchain.
A network of channels
You don't need a channel with everyone. Payments route through other people's channels, secured so that intermediaries can't steal the money. See HTLCs: hash time-locked contracts.
Trade-offs
| Strength | Limitation |
|---|---|
| Payments in seconds | You need channel liquidity |
| Fees often a few sats | Your node should be online, or use a watchtower |
| Many payments leave no on-chain trace | Opening and closing channels cost on-chain fees |
| Amounts down to millisatoshis | Large payments may struggle to find a route |
Lightning vs on-chain Bitcoin
| On-chain | Lightning | |
|---|---|---|
| Speed | About 10 minutes per confirmation | Seconds |
| Fees | Depend on block space demand | Usually a few sats |
| Best for | Savings, large amounts | Small, frequent payments |
| Record | Public blockchain | Only channel opens and closes are on-chain |
| Smallest amount | 1 sat (dust limits apply) | 1 millisatoshi |
Getting started
Install a Lightning wallet, receive a small amount, then pay a Lightning invoice. Many wallets manage channels automatically so you never see them.
Key takeaways
- Lightning moves payments into off-chain channels secured by Bitcoin.
- Payments route across channels via intermediaries.
- It's fast and cheap, but needs liquidity and online nodes.
Common questions
Is Lightning a different coin?
No. It uses real bitcoin locked in on-chain channels.
Do I need to run a Lightning node?
Not necessarily. Many mobile wallets manage channels for you, some custodially. Running your own gives full control.
Is Lightning safe?
Funds are secured by Bitcoin contracts, but you or a watchtower must watch for cheating, and wallets are newer and more complex than on-chain ones.
Can Lightning payments be traced?
They leave far less public trace than on-chain payments, though channel opens and closes are visible on the blockchain.