Bitcoin for Savers Using it safely

Lightning payments: sending and receiving sats

Fast, cheap payments for everyday amounts. Learn how invoices work, how to receive and send, and what to check before you pay.

12 minBeginner5 / 8

Draft: this lesson is still waiting for review.

What you'll learn

Explain when to use Lightning instead of an on-chain payment
Read an invoice and find its amount, description and expiry
Check a payment request safely before you pay

Key terms

Lightning Network (mtandao wa Lightning): A network on top of Bitcoin for fast payments with very small fees.
invoice (ankara): A Lightning payment request, often shown as a QR code, with an amount and an expiry time.
QR code (msimbo wa QR): A square of dots a phone camera can read, often holding an address or invoice.
fee (ada): A small amount you pay to get your transaction into a block or routed over Lightning.
confirmation (uthibitisho): A transaction gets one confirmation when it enters a block; each later block adds another.
channel (chaneli): A payment link between two Lightning nodes, locked by a Bitcoin transaction.

Otieno sells chapati near a matatu stage. A customer wants to pay 50 shillings in sats. Waiting ten minutes for a block, and paying a fee larger than the chapati, makes no sense. This is what the Lightning Network is for.

On-chain or Lightning?

An on-chain payment is written straight into the blockchain. It gets its first confirmation when it enters a block, about every 10 minutes, and its fee depends on how busy the network is. It suits large or long-term amounts.

Lightning is a network built on top of Bitcoin. Payments travel through channels between Lightning nodes and arrive in seconds, usually for a fee of a few sats. It suits small, everyday payments.

Invoices

To receive on Lightning, your wallet makes an invoice: a payment request, usually shown as a QR code. The text form is long and starts with lnbc. An invoice contains:

the amount in sats,
a description, such as "2 chapati, Otieno's",
an expiry time, often about an hour, after which it can't be paid.

Each invoice is meant to be paid once. Many wallets also offer a Lightning address that looks like an email, such as otieno@example.com, which can receive many payments.

Receiving and sending

To receive: open your wallet, tap Receive, enter the amount, and show the QR code or share the invoice.

To send: tap Send or Scan, scan the QR code, then read the amount and description before you confirm.

Try it

Next time you see any payment QR code, at a shop, on a poster or in a message, stop and say out loud: "Who am I paying, how much, and for what?" If you already use a Lightning wallet, ask a friend for an invoice of 10 sats and find the amount, description and expiry before you pay it.

Practise this concept

Lightning channel balances
Move example sats between Alice and Bob and watch the direction-dependent balance change.

Reflect

Write your answer down, or talk it over with a friend or your chama.

Which payments in your week would suit Lightning, and which would suit an on-chain payment?
What would you say to a shopkeeper who wants to accept sats but is afraid of fake QR codes?