The Lightning Network, explained

What Lightning is for

Bitcoin’s base chain is good at final settlement, but every payment competes for scarce block space and waits for confirmations. The Lightning Network is a layer built on top of Bitcoin for smaller, frequent payments that need to arrive in seconds rather than tens of minutes. Two parties lock some bitcoin into a shared channel on the chain, then update who owns what inside that channel without touching the chain for every payment.

Only the opening and closing transactions need Bitcoin block space. Everything in between is off-chain. That usually makes Lightning cheap and fast for everyday transfers, tipping, top-ups and moving small amounts between services that both support it.

Channels and routing

A channel is a pot of bitcoin shared between two nodes. If you open a channel with 500,000 sats, you start with all 500,000 sats on your side. As you pay through that channel, some balance moves to the remote side. Your ability to send depends on how much balance is on your side; your ability to receive depends on how much room is on the remote side. That is what Lightning users mean by liquidity.

You do not need a direct channel to every payee. Lightning payments are routed across several connected nodes. Each hop forwards the payment for a small fee, and the route succeeds only if every hop has enough liquidity for that amount. A payment can fail even when the invoice is valid, simply because no route with enough room is available at that moment.

Channels are also not forever. Either side can close and settle the latest valid state back to Bitcoin. A cooperative close is usually tidy and cheap; a force-close is slower and can lock funds until the relevant timelocks expire. That is one reason self-custodial Lightning asks more of you than an ordinary on-chain wallet.

Invoices and what BOLT 11 means

Most Lightning payments use an invoice: a payment request starting with lnbc for Bitcoin mainnet. The common format is called BOLT 11, defined in the Lightning specification. An invoice includes the amount, a description, an expiry time and the payee’s routing hints if needed.

Unlike a Bitcoin address, a Lightning invoice is usually single-use and often time-limited. If it expires, the payer must ask for a new one. Some wallets and merchants also use static Lightning Addresses or LNURL, but they still turn into a fresh invoice before payment. Our Lightning invoice decoder shows what an invoice is asking you to pay before you send it.

Custodial and self-custodial wallets

A custodial Lightning wallet runs the node and channels for you. You log in to an account and the provider keeps track of your balance. It is simple, usually works well for receiving and sending, and can recover your account if you lose your phone. The trade-off is trust: the provider can freeze access, analyse your payments or fail as a business.

A self-custodial wallet keeps control of the keys and, depending on the design, either runs your own channels or uses a service only for routing. That gives you more independence and better privacy, but it also means backups matter more. With a pure channel wallet, restoring from an old backup can be awkward because the state of each channel keeps changing. Many modern wallets therefore use hybrids that hold keys locally but rely on a provider for channels.

• Use custodial Lightning for convenience and small spending balances only.
• Use self-custodial Lightning when you want control, better privacy or to learn how channels work.
• Keep larger savings on the Bitcoin base chain, not in a Lightning wallet.

When Lightning makes sense

Lightning is strongest when the payment is small, speed matters and both sides already support it. Examples include buying a coffee, topping up a service, moving funds between two exchanges that both accept Lightning, or paying a merchant that gives a discount for it. It is often cheaper than an on-chain payment when chain fees are high, and it avoids waiting for block confirmations.

It is less suitable when you need the simple permanence of an on-chain payment, when the amount is large relative to typical channel sizes, or when the sender or receiver may need an exact audit trail on the base chain. For a large withdrawal to self-custody, many people still prefer ordinary Bitcoin. The right comparison is not “better” or “worse”, but which settlement rail fits this payment.

A useful rule is this: keep long-term savings and important receipts on the base chain, and use Lightning as the spending layer when convenience matters more than leaving every step on-chain. That matches how many exchanges, merchants and wallet users already treat it in practice.

Practical habits

• Check whether a service supports Lightning deposits and withdrawals before you move funds there.
• Decode invoices before paying, especially if the amount is hidden in your wallet’s UI.
• Keep only spending money in Lightning; move reserves back on-chain for long-term storage.
• If you use self-custodial Lightning, test your backup and recovery process before you need it.
• For on-chain fee context, use Bitcoin fees and the mempool and the live fee estimator.