ℹ️ NOTE: This is a draft in progress, so that I can get some feedback from early reviewers. It is not yet ready for learning.
In this chapter you will learn how to pay an invoice using lightning-cli pay command. As we did in previous chapter we already have an invoice to pay.
Check ln invoice:
lntb1m1p03ft7lpp5zve4dsgwgdxekqqq39vhgcnv6gfa2g2ktqy9lf0aph60d0388xmqdqqcqzpgsp545a9fphd8m5ayplcu8m5845cr4m0zcnyxddwv4g3zm32yprkfd4q9qy9qsq3s4y6cmyvh0qw9qm0sf80llxyyjy9xwrjds7lpkqhzv247jsm6q5me8t9e6ftquma664gz5u4a2rvs0yf4f0mlwtwfs6as5uj5djzhcqpnqlcj
This invoice starts with prefix ln+tb+1m that indicates milli, so you should multi by 0.001. That means we'll pay an invoice by 100000 satoshis.
If you want to decode your lightning invoice you should use lightning-cli decodepay command that receives a string and checks and parses as specified by the BOLT 11 specification.
On success it returns an object with the following fields:
- currency: Currency.
- timestamp: the UNIX-style timestamp of the invoice.
- expiry: the number of seconds this is valid after timestamp.
- payee: the public key of the recipient.
- payment_hash: the payment hash of the request.
- signature: the DER-encoded signature.
- description: Description.
c$lightning-cli --network=testnet decodepay lntb1m1p03ft7lpp5zve4dsgwgdxekqqq39vhgcnv6gfa2g2ktqy9lf0aph60d0388xmqdqqcqzpgsp545a9fphd8m5ayplcu8m5845cr4m0zcnyxddwv4g3zm32yprkfd4q9qy9qsq3s4y6cmyvh0qw9qm0sf80llxyyjy9xwrjds7lpkqhzv247jsm6q5me8t9e6ftquma664gz5u4a2rvs0yf4f0mlwtwfs6as5uj5djzhcqpnqlcj
{
"currency": "tb",
"created_at": 1595191263,
"expiry": 3600,
"payee": "0302d48972ba7eef8b40696102ad114090fd4c146e381f18c7932a2a1d73566f84",
"msatoshi": 100000000,
"amount_msat": "100000000msat",
"description": "First LN Payment - Learning Bitcoin and Lightning from the Command line.",
"min_final_cltv_expiry": 40,
"payment_secret": "ad3a5486ed3ee9d207f8e1f743d6981d76f16264335ae6551116e2a204764b6a",
"features": "028200",
"payment_hash": "133356c10e434d9b0000895974626cd213d5215658085fa5fd0df4f6be2739b6",
"signature": "30450221008c2a4d636465de07141b7c1277ffe621244299c39361ef86c0b898aafa50de8102204de4eb2e7495839beeb5540a9caf543641e44d52fdfdcb7261aec29c951b215f"
}
Check payee value is the same as identity_pubkey value seen previous chapter.
"identity_pubkey": "0302d48972ba7eef8b40696102ad114090fd4c146e381f18c7932a2a1d73566f84",
As we did in previous chapter we have established an channel with a total capacity of 280.000 sats. This will be channel used to pay the invoice.
c$ lightning-cli --network=testnet listfunds
{
"outputs": [
{
"txid": "9843c037f54a4660b297a9f2454e11d26d8659f084a284a5740bb15cb1d97aa6",
"output": 0,
"value": 19238,
"amount_msat": "19238000msat",
"scriptpubkey": "0014aa572371f29310cd677d039cdcd054156c1a9545",
"address": "tb1q4ftjxu0jjvgv6emaqwwde5z5z4kp49299gmdpd",
"status": "confirmed",
"blockheight": 1780768,
"reserved": false
}
],
"channels": [
{
"peer_id": "0302d48972ba7eef8b40696102ad114090fd4c146e381f18c7932a2a1d73566f84",
"connected": true,
"state": "CHANNELD_AWAITING_LOCKIN",
"channel_sat": 280000,
"our_amount_msat": "280000000msat",
"channel_total_sat": **280000**,
"amount_msat": "280000000msat",
"funding_txid": "9843c037f54a4660b297a9f2454e11d26d8659f084a284a5740bb15cb1d97aa6",
"funding_output": 1
}
]
}
You should use lightning-cli pay command to pay the invoice. The pay RPC command attempts to find a route to the given destination, and send the funds asked in amount value.
Notice amount is expressed in milli-satoshi.
c$lightning-cli --network=testnet pay
lntb1m1p03ft7lpp5zve4dsgwgdxekqqq39vhgcnv6gfa2g2ktqy9lf0aph60d0388xmqdqqcqzpgsp545a9fphd8m5ayplcu8m5845cr4m0zcnyxddwv4g3zm32yprkfd4q9qy9qsq3s4y6cmyvh0qw9qm0sf80llxyyjy9xwrjds7lpkqhzv247jsm6q5me8t9e6ftquma664gz5u4a2rvs0yf4f0mlwtwfs6as5uj5djzhcqpnqlcj
{
"id": 1,
"payment_hash": "133356c10e434d9b0000895974626cd213d5215658085fa5fd0df4f6be2739b6",
"destination": "0302d48972ba7eef8b40696102ad114090fd4c146e381f18c7932a2a1d73566f84",
"msatoshi": 100000000,
"amount_msat": "100000000msat",
"msatoshi_sent": 100000000,
"amount_sent_msat": "100000000msat",
"created_at": 1595191379,
"status": "complete",
"payment_preimage": "8b7549ffd4e648374669d47992c1ab44086501d5dd85d7e3d15766d70e9196e3",
"bolt11": "lntb1m1p03ft7lpp5zve4dsgwgdxekqqq39vhgcnv6gfa2g2ktqy9lf0aph60d0388xmqdqqcqzpgsp545a9fphd8m5ayplcu8m5845cr4m0zcnyxddwv4g3zm32yprkfd4q9qy9qsq3s4y6cmyvh0qw9qm0sf80llxyyjy9xwrjds7lpkqhzv247jsm6q5me8t9e6ftquma664gz5u4a2rvs0yf4f0mlwtwfs6as5uj5djzhcqpnqlcj"
}
We've performed payment successfully and gets decreased channel balance on our side. Now it has 180000 as available balance.
c$ lightning-cli --network=testnet listfunds
{
"outputs": [
{
"txid": "9843c037f54a4660b297a9f2454e11d26d8659f084a284a5740bb15cb1d97aa6",
"output": 0,
"value": 19238,
"amount_msat": "19238000msat",
"scriptpubkey": "0014aa572371f29310cd677d039cdcd054156c1a9545",
"address": "tb1q4ftjxu0jjvgv6emaqwwde5z5z4kp49299gmdpd",
"status": "confirmed",
"blockheight": 1780768,
"reserved": false
}
],
"channels": [
{
"peer_id": "0302d48972ba7eef8b40696102ad114090fd4c146e381f18c7932a2a1d73566f84",
"connected": true,
"state": "CHANNELD_NORMAL",
"short_channel_id": "1780768x12x1",
"channel_sat": 180000,
"our_amount_msat": "180000000msat",
"channel_total_sat": 280000,
"amount_msat": "280000000msat",
"funding_txid": "9843c037f54a4660b297a9f2454e11d26d8659f084a284a5740bb15cb1d97aa6",
"funding_output": 1
}
]
}
We've created an invoice by 100.000 satoshis using a second machine and we've payed it using our main Lightning network node c-lightning. The channel was created with an initial amount of 280000 satoshis. This is called Total capacity channel. Later we've payed invoice we proved local balance was reduced remaining at 180.000 satoshis.
Continue "Understanding Your Lightning Setup" with §19.3: Closing a Channel.