Lightning Network

The Lightning Network is a Layer 2 scaling solution for Bitcoin that enables instant, low-cost payments. It's the backbone of Nostr's payment infrastructure.

What is Lightning Network?

Lightning is a network of payment channels built on top of Bitcoin:

Key Properties

Property	Bitcoin On-Chain	Lightning
Speed	10-60 minutes	Milliseconds
Fees	Variable ($0.50-$50+)	Near-zero ($0.001)
Throughput	~7 TPS	1,000,000+ TPS
Privacy	Public ledger	Route-based
Minimum	Dust limit (~$3)	1 satoshi

How Lightning Works

Payment Channels

1. Opening: Fund a channel with on-chain Bitcoin
2. Transacting: Unlimited off-chain payments
3. Closing: Settle final balance on-chain

Alice can send up to 1 BTC to Bob without touching the blockchain.

Routing

Payments route through multiple channels:

Each node charges a small routing fee.

Lightning on Nostr

Integration Points

1. Zaps - NIP-57 Lightning payments
2. NWC - NIP-47 Wallet connectivity
3. LNURL - Simplified payment flows
4. Marketplace - Product payments

LNURL

LNURL simplifies Lightning interactions:

LNURL Type	Purpose
lnurl-pay	Receive payments
lnurl-withdraw	Claim payments
lnurl-auth	Authentication
lnurl-channel	Open channels

Lightning Address

Human-readable payment addresses:

user@domain.com → LNURL-pay endpoint

Behind the scenes:

GET https://domain.com/.well-known/lnurlp/user
Returns: Payment endpoint metadata

Setting Up Lightning

Option 1: Custodial Wallets

Easiest for beginners:

Wallet	Features
Wallet of Satoshi	Simple, no setup
Alby	Browser extension
Strike	Easy fiat on-ramp

Option 2: Self-Custodial

More control, more responsibility:

Wallet	Features
Phoenix	Mobile, auto channels
Mutiny	Web-based, private
Zeus	Full node control
Breez	POS features

Option 3: Full Node

Maximum sovereignty:

# Example: Running a node
- Bitcoin Core (base layer)
- LND / CLN / Eclair (Lightning implementation)
- RTL / ThunderHub (management UI)

Lightning Invoices

Invoice Structure

Component	Example	Description
Network prefix	lnbc	mainnet
Amount	1000n	1000 sats
Data payload	1pj...	Payment hash, etc.

Invoice Fields

Field	Description
Amount	Payment amount in sats
Payment Hash	Unique payment identifier
Expiry	Time until invoice expires
Description	Payment memo
Route Hints	Help find recipient

Creating Invoices

Via NWC:

{
  "method": "make_invoice",
  "params": {
    "amount": 1000,
    "description": "Thanks for the content!"
  }
}

Lightning Limitations

Channel Capacity

• Maximum payment = smallest channel in route
• Large payments may fail
• Solution: Multiple smaller payments or MPP

Inbound Liquidity

To receive, you need inbound capacity:

Solutions:

• Buy inbound liquidity
• Spend first to create inbound
• Use services like Loop

Online Requirement

• Must be online to receive
• Watchtowers can protect channels
• Custodial solutions avoid this

Lightning + Nostr Flow

Sending a Zap

1. User clicks ⚡ on post
2. Client creates Zap Request
3. Sends to recipient's LNURL
4. LNURL returns invoice
5. Client pays via NWC
6. Wallet pays Lightning invoice
7. LNURL publishes Zap Receipt

Receiving Payments

1. Set lud16 in profile
2. Point to LNURL endpoint
3. Endpoint handles:
   - Invoice generation
   - Payment receipt
   - Zap receipt publishing

Best Practices

For Users

1. Start custodial - Learn before self-custody
2. Fund appropriately - Keep small amounts for zapping
3. Multiple wallets - Separate spending/savings
4. Backup keys - Protect wallet seeds

For Developers

1. Use NWC - Standard wallet connection
2. Handle failures - Lightning can timeout
3. Implement LNURL - Better UX
4. Test on testnet - Before mainnet

On-Chain

While Lightning is the primary payment method on Nostr, on-chain Bitcoin payments are still useful for:

• Large amounts where Lightning capacity is insufficient
• Long-term savings
• Channel funding
• Cold storage deposits

On-Chain vs Lightning

Use Case	Recommended
Zaps and tips	Lightning
Small purchases	Lightning
Large payments (1000+ USD)	On-chain
Savings	On-chain
Channel deposits	On-chain

On-Chain in Nostr

On-chain payments aren't directly integrated into Nostr protocols yet, but you can:

• Share on-chain addresses in DMs
• Use NIP-15 marketplace with on-chain option
• Include Bitcoin addresses in profiles

Resources

Wallets

• Alby - Browser extension
• Phoenix - Mobile
• Mutiny - Web
• Zeus - Mobile + node

Learning

• Lightning Network Whitepaper
• BOLT Specifications
• LNURL Specifications

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Micropayments Unlocked

Lightning makes payments of 1 sat (~$0.001) economically viable. This enables entirely new business models impossible with traditional payment systems.