Lightning Network

The Lightning Network is a second-layer payment system built on top of Bitcoin that enables near-instant, very low-fee payments by keeping most transactions off the main blockchain. Instead of recording every payment on-chain, two parties lock bitcoin into a shared payment channel and update balances between themselves; the blockchain is only involved when the channel opens or closes.

Payments can also hop across multiple channels, so you can pay someone you have no direct channel with, routed through intermediate nodes. A concrete example: a customer with a Lightning wallet scans a coffee shop's QR code and pays 3,000 satoshis; the payment routes through the network and confirms in about a second for a fee of a few satoshis — economics that would be impossible on the Bitcoin base layer, where a single transaction can cost more than the coffee during busy periods. El Salvador's Bitcoin rollout and various tipping and podcast apps have used Lightning for exactly this kind of small, fast payment.

Lightning's security comes from Bitcoin itself: channel balances are enforceable on-chain, so counterparties cannot steal funds without being penalized, though users (or their wallet providers) must watch for fraudulent channel closes. Practical limitations include the need for inbound liquidity to receive payments, occasional routing failures for larger amounts, and the fact that many consumer wallets are custodial, which trades away self-custody for convenience. A common misconception is that Lightning is a separate cryptocurrency; it is not — every Lightning payment is denominated in and backed by real bitcoin.