The Lightning Network is a second layer built on top of Bitcoin. Two parties lock bitcoin into a shared on-chain output and then trade signed balance updates off-chain. Payments can be routed across a chain of these channels, so the blockchain only records the channel opening and closing. Payments settle in seconds, and routing fees are a small fraction of the amount. The money is always real BTC: the network has no token of its own. Lightning has trade-offs, though. Public capacity is down from its 2025 peak, users have to manage liquidity, and some known attacks are still not fully solved.
Latest developments (October 2026)
- 23 October 2026: Lightning Labs put Wavelength live on Bitcoin mainnet. It is a toolkit for adding self-custodial bitcoin payments to apps without running a node or managing channels. It settles over Lightning and what the company calls an "Ark-like settlement layer." The release is still labelled alpha. Each mainnet account is capped at 300,000 sats, and stablecoin payments are listed as "coming soon."
- 25 August 2026: mempool.space's public Lightning statistics show 33,283 public channels holding 384,310,751,017 sats, about 3,843 BTC. That is roughly a third below the 5,637 BTC that Bitcoin Magazine reported from AMBOSS data on 17 December 2025.
- 23 June 2026: Lightning Labs released Taproot Assets v0.8, with the first public SDK for issuing and moving assets such as stablecoins over Lightning.
- 11 June 2026: LND v0.21-beta added onion messaging, which Lightning Labs calls a first step toward BOLT12 support. It also marked simple taproot channels as production-ready on mainnet and added fee bumping (RBF) for cooperative channel closes.
Public statistics only count announced channels. Private channels, which many mobile wallets use, are not included, so the totals above understate the whole network.
How the Lightning Network works
The design comes from Joseph Poon and Thaddeus Dryja's paper The Bitcoin Lightning Network: Scalable Off-Chain Instant Payments. Its widely cited version is Draft 0.5.9.2, dated 14 January 2016. Lightning Labs released lnd 0.4-beta on 15 March 2018 as the first Lightning beta for mainnet, and advised users to start with small amounts.
Payment channels
- Open. Two parties sign an on-chain funding transaction. It locks bitcoin into an output that needs both of their signatures to spend.
- Update. Each payment creates a new commitment transaction showing the new balance split, and both parties sign it. Older states are revoked. Nothing reaches the blockchain at this stage.
- Close. The parties can close the channel together, or either one can close it alone by broadcasting the latest commitment transaction. After a one-sided close, the party who broadcast must wait out a relative timelock (
to_self_delay, enforced withOP_CHECKSEQUENCEVERIFY) before spending their own output.
The penalty for cheating
If someone broadcasts an outdated commitment transaction, the other party can sweep the cheater's funds using the revocation key. The protocol rules are in the BOLT 5 specification. This only works if the honest party sees the breach before the timelock runs out. For that reason, nodes stay online or use watchtowers. A watchtower is a service that watches the chain for breaches on a node's behalf. In LND it is a feature you must turn on, and LND's documentation suggests hosting it on a separate machine, network and location.
Routing and HTLCs
If Alice has no channel with Carol, she can still pay her through Bob, as long as Bob has channels with both of them. Hashed Timelock Contracts (HTLCs) link each hop to the same payment hash. Either every hop settles or none does. Route information is wrapped in layered encryption ("onion-style routing," BOLT 4), so each node handling the payment learns only the hop before it and the hop after it.
Invoices
A standard request for payment is a BOLT11 invoice. On Bitcoin mainnet it starts with lnbc. It carries the amount, the payment hash and an expiry. If the invoice does not set an expiry, the default is 3,600 seconds (one hour).
What Lightning payments cost
Each node that forwards a payment sets its own fee. The BOLT 7 formula is:
fee = fee_base_msat + (amount × fee_proportional_millionths / 1,000,000)
In the 25 August 2026 mempool.space snapshot, the median base fee is 500 millisatoshis (half a satoshi). The median proportional rate is 103 parts per million, or about 0.01%. At that rate, a route through one median-priced hop costs about one cent in proportional fees on a $100 payment, plus the base fee. Each extra hop adds another fee.
Lightning does not remove on-chain costs. You still pay normal Bitcoin network fees to open a channel, to close one, and to swap between on-chain and Lightning funds. Wallets that manage channels for you also charge for the inbound liquidity they supply. Check your wallet's current fee page before you fund it.
Liquidity: why a new wallet sometimes cannot receive
- Outbound liquidity is the bitcoin on your side of a channel. It is what you can send.
- Inbound liquidity is the bitcoin on the other side. It is what you can receive.
If you open a channel and put in 0.01 BTC, you can send up to that amount but receive nothing until funds move to the other side. Managed self-custodial wallets solve this by having a Lightning Service Provider (LSP) open channels or add capacity for you. Bitcoin.org's wallet listing says Phoenix, from ACINQ, manages channel liquidity automatically. If you run your own node, you manage liquidity yourself. In the August 2026 snapshot, the average public channel held about 0.115 BTC, and a single payment cannot exceed the liquidity available along its route.
Custodial and self-custodial wallets
| Custodial | Self-custodial | |
|---|---|---|
| Who holds the keys | The provider | You |
| Setup | Minimal | Moderate: you keep a seed backup |
| Main risk | The provider fails, freezes or loses funds | Losing your backup, or a device compromise |
| Channel management | Done by the provider | Automatic in managed wallets; manual on your own node |
Lightning keys sit on a device that is online, which makes a Lightning wallet a hot wallet. Many users treat it like a physical wallet: enough for spending, with long-term savings kept on-chain.
What will routing fees cost you?
Enter a payment amount, the number of forwarding hops and each hop's fee settings to see the total routing fee under the BOLT 7 formula.
| Payment amount | Forwarding hops on the route | Base fee charged by each hop | Proportional rate charged by each hop | Total routing fee |
|---|---|---|---|---|
| 300,000 sats | 1 hops | 500 msat | 103 ppm | 31.4 sats |
| 300,000 sats | 2 hops | 500 msat | 103 ppm | 62.8 sats |
| 100,000 sats | 1 hops | 1,000 msat | 500 ppm | 51 sats |
- Every hop is treated as charging the same base fee and rate; on a real route each node sets its own.
- Fee values are your own inputs; the defaults are snapshot medians, not what any given route will charge.
This covers routing fees only: it leaves out on-chain fees to open, close or swap, wallet liquidity charges, and whether a route with enough liquidity exists.
Known risks and open problems
- Channel jamming. This is a denial-of-service attack that can tie up liquidity in channels up to 20 hops away. Bitcoin Optech notes that no complete fix has wide support yet. Implementations are trying partial measures, such as experimental local reputation scoring in LND.
- Replacement cycling. This attack was disclosed on the bitcoin-dev mailing list in October 2023. An attacker can repeatedly remove a victim's time-sensitive transaction from node mempools, which puts HTLCs at risk. Lightning implementations have deployed mitigations such as frequent rebroadcasting and longer timeouts. Keep wallet and node software up to date.
- Being offline. A self-custodial user who is offline past the timelock, with no watchtower, cannot punish a revoked-state broadcast.
- Locked-up capital. Bitcoin in a channel cannot be spent on-chain until the channel closes or the funds are swapped out.
Stablecoins and other assets on Lightning
Taproot Assets is Lightning Labs' protocol for issuing assets on Bitcoin and moving them through Lightning channels. Bitcoin and an asset can share channel funding in the same output, and edge nodes can offer atomic conversion between bitcoin and the asset.
- 30 January 2025: Tether announced plans to bring USDt to Bitcoin and Lightning using Taproot Assets. The announcement used future tense: "Once fully integrated…"
- 24 June 2025: Taproot Assets v0.6 brought stablecoin transfers over Lightning, according to Lightning Labs.
- 16 December 2025: v0.7 added static, reusable addresses (AddressV2), auditable grouped-asset supply, and multi-path ("Multi-RFQ") sends for larger transfers.
- 23 June 2026: v0.8 added the SDK and wallet backup and restore.
Does the Lightning Network have a token?
No. Every Lightning payment is denominated in bitcoin, down to millisatoshis for routing. Any "Lightning token" or "LN coin" sold as an investment is not part of the protocol.
Sending and receiving: the basics
Receiving
Open your wallet and choose Receive. Create an invoice, with or without an amount, and share it as a QR code or an lnbc… string. Many wallets also offer a Lightning Address, a reusable identifier that looks like an email address.
Sending
Scan or paste the invoice, check the amount and description, and confirm. The wallet finds the route. Lightning payments cannot be reversed, so check before you confirm. If a large payment fails, a wallet that supports multi-path payments may split it across routes, or you can try a smaller amount.
FAQ
Is the Lightning Network safe?
The protocol relies on Bitcoin transactions and timelocks rather than trust in a counterparty. The practical risks are custodial providers, lost backups, compromised hot devices, and the open problems listed above.
Can I always get my bitcoin back on-chain?
With a self-custodial wallet you can close a channel by yourself and recover your balance on the Bitcoin blockchain after the timelock. With a custodial wallet, getting your funds out depends on the provider.
Why is public capacity falling if development is active?
Public capacity counts only announced channels. It reached 5,637 BTC in December 2025 according to AMBOSS data reported by Bitcoin Magazine, and stood at about 3,843 BTC on 25 August 2026 in mempool.space data. The figure measures bitcoin committed to public channels, not payment volume or private-channel use.
Limitations: network figures come from public explorers that cannot see private channels. Wavelength and the Taproot Assets figures come from Lightning Labs' own announcements.
